bluuebunny/crossref_metadata_2025 huggingface dataset:
Knowledge spillovers and the assignment of R&D responsibilities to foreign subsidiaries
Authors: Feinberg Susan E. , Gupta Anil K.
Published: July 2004

Research on R&D location choice by MNCs has focused largely on host country factor endowments and overlooked the role that the potential to capture and utilize knowledge spillovers from competitors may also play in determining such choices. Using a large‐scale panel database of the foreign subsidiaries of U.S.‐based MNCs in above‐average R&D‐intensive industries, we examine the extent to which external spillover opportunities as well as internal firm‐specific capabilities to utilize such knowledge affect MNCs' new R&D location decisions. Our findings suggest that MNCs appear to anticipate potential spillover opportunities and are discriminating in assessing these opportunities not only across locations but also across categories of competitors within the same location. Further, our findings provide stronger support to predictions regarding the salience of global utilization capacity than they do to predictions regarding the salience of local utilization capacity. Copyright © 2004 John Wiley & Sons, Ltd.
Where do resources come from? The role of idiosyncratic situations
Authors: Ahuja Gautam , Katila Riitta
Published: July 2004

In this paper, we examine the emergence of resources. Our analysis of technological capability acquisition by global U.S.‐based chemical firms shows that the emergence of resources is inherently evolutionary. We find thatpath‐creating searchthat generates resource heterogeneity is a response to idiosyncratic situations faced by firms in their local searches. Two such idiosyncratic situations—technology exhaustion and expansion beyond national markets—trigger firms in our sample to create unique innovation search paths. We also find that along a given path firms experiment in order to find the correct investment—in fact, some organizations seem to take a step backward for two steps forward—further demonstrating the evolutionary nature of the resource creation process. Copyright © 2004 John Wiley & Sons, Ltd.
Momentum and serendipity: how acquired leaders create value in the integration of technology firms
Authors: Graebner Melissa E.
Published: July 2004

Merger and acquisition activity is a critical means by which technology firms obtain the resources needed to compete in global markets. Effective implementation is essential to making these acquisitions successful, yet prior research on the implementation process has yielded paradoxical findings. I argue that a closer examination of the role of the acquired managers helps to resolve the implementation dilemmas found in prior research, which has focused on the role of the acquiring firm. I use grounded theory‐building techniques to examine the integration of eight technology acquisitions, and find that acquired managers play a key role in achieving two types of value: expected and serendipitous. In promoting the realization of these two types of value, acquired leaders maintain the advantages of both integration and autonomy. Moreover, these leaders enable their organizations to simultaneously experience two often‐conflicting forms of change: exploration and exploitation. Copyright © 2004 John Wiley & Sons, Ltd.
The global acquisition, leverage, and protection of technological competencies
Authors: McEvily Susan K. , Eisenhardt Kathleen M. , Prescott John E.
Published: July 2004

How managers acquire, leverage, and protect technological competencies in order to innovate successfully and enhance firm performance is central to the field of strategic management. When tensions across acquisition, leverage, and protection activities are resolved and synergies are captured, the value derived from technological competencies can be used to fuel a virtuous cycle in which fewer resources are needed to perpetuate a firm's advantage. The papers in this issue examine the mechanisms underlying acquisition, leverage, and protection, and are particularly useful in resolving these tensions and highlighting potential synergies. We develop a typology to describe the research domain and relate these papers to one another. Based on gaps in this typology and issues raised by these papers, we offer observations for future research on the acquisition, leverage, and protection of technological competencies. Copyright © 2004 John Wiley & Sons, Ltd.
Geography, empire and sainthood in the eighteenth-century Muslim Deccan
Authors: GREEN NILE
Published: July 2004

This article examines the relationship between the Mughal colonization of the Deccan during the twelfth/eighteenth century and the development of the Sufi traditions of Awrangabad. Concurrent with the defeat of the Deccan sultanates was a process of re-ordering the sacred Muslim landscape of the Deccan into harmony with the cultural and political values of the region's new elites by the importation of Sufi traditions from the north. As a reflection of the wider cultural make-up of the Mughal world, questions of regional, political and ethnic affiliation were articulated by writers whose own remembered homelands lay far from the Deccan. Placing Sufi commemorative texts written in Awrangabad into a wider social and literary context, the article discusses the place of the city's Sufis in the social, political and intellectual life of a short-lived imperial centre. The city's saints are in this way seen as the most semantically rich of all the cultural products of the period.
A high‐resolution GIS‐based inventory of the west Siberian peat carbon pool
Authors: Sheng Yongwei , Smith Laurence C. , MacDonald Glen M. , Kremenetski Konstantine V. , Frey Karen E. , Velichko Andrei A. , Lee Mary , Beilman David W. , Dubinin Peter
Published: July 2004

The West Siberian Lowland (WSL) contains the world's most extensive peatlands and a substantial fraction of the global terrestrial carbon pool. Despite its recognition as a carbon reservoir of great significance, the extent, thickness, and carbon content of WSL peatlands have not been analyzed in detail. This paper compiles a wide array of data into a geographic information system (GIS) to create a high‐resolution, spatially explicit digital inventory of all WSL peatlands and their associated physical properties. Detailed measurements for nearly 10,000 individual peatlands (patches) are based on compilation of previously unpublished Russian field and ancillary map data, satellite imagery, previously published depth measurements, and our own field depth and core measurements taken throughout the region during field campaigns in 1999, 2000, and 2001. At the patch level, carbon storage is estimated as the product of peatland area, depth, and carbon content. Estimates of peatland area are validated from RESURS‐01 satellite images, and the quality of the Russian peatland depth and carbon content data is independently confirmed by laboratory analysis of core samples. Through GIS‐based spatial analysis of the peat areal extent, depth, and carbon content data, we conservatively estimate the total area of WSL peatlands at 592,440 km2, the total peat mass at 147.82 Pg, and the total carbon pool at 70.21 Pg C. Our analysis concludes that WSL peatlands are more extensive and represent a substantially larger carbon pool than previously thought: Previous studies report 9,440–273,440 km2 less peatland area and 15.11–30.19 Pg less carbon than found in this analysis. The complete digital database is freely available for scientific use at http://arcss.colorado.edu/data/arcss131.html.
Long‐term variability of [SII] emissions from the Io plasma torus between 1997 and 2000
Authors: Nozawa H. , Misawa H. , Takahashi S. , Morioka A. , Okano S. , Sood R.
Published: July 2004

Long‐term optical observation of the Io plasma torus provides a great deal of information on the plasma environment in the Jovian magnetosphere. We made imaging observations of [SII] emissions (λλ 673.1, 671.6 nm) from the Io plasma torus using a transportable telescope system for the period from 1997 to 2000. From the data we obtained intensity variations and average radial profiles and found that the plasma torus underwent systematic long‐term variations between 1997 and 2000, indicating that Io's volcanic activity has been reducing over the years. We investigated the periodicity of torus emission intensity and confirmed that torus plasma is modulated at about 10.2 hours, corresponding to the so‐called System IV period, and that the torus has no long‐term System III periodicity.
Aerosol optical characterization by nephelometer and lidar: The Baltimore Supersite experiment during the Canadian forest fire smoke intrusion
Authors: Adam Mariana , Pahlow Markus , Kovalev Vladimir A. , Ondov John M. , Parlange Marc B. , Nair Narayanan
Published: July 2004

High spatial and temporal resolution elastic backscatter lidar data from Baltimore are analyzed with a near‐end approach to estimate vertical profiles of the aerosol extinction coefficient. The near‐end approach makes use of the (1) aerosol scattering coefficient measured at the surface with a nephelometer (0.530 μm), (2) surface level particle size distribution, and (3) refractive index calculated using Mie theory to estimate the aerosol extinction coefficient boundary condition for the lidar equation. There was a broad range of atmospheric turbidity due to a strong haze event, which occurred because of smoke transport from Canadian forest fires, and led to a wide range of observed atmospheric properties. The index of refraction for aerosols estimated during the entire study period is 1.5–0.47 i, which is typical for soot. The measured surface level aerosol scattering coefficient ranged from σp = 0.002 to σp = 0.541 km−1, and the computed aerosol extinction coefficient spanned values κp = 0.01 to κp = 1.05 km−1. The derived mass concentration and the mass scattering ranges were 3.96–194 μg m−3 and 0.05–3.260 m2g−1, respectively. The aerosol optical properties were dominated by light absorption by soot.
Occurrence characteristics of medium‐scale gravity waves observed in OH and OI nightglow over Adelaide (34.5°S, 138.5°E)
Authors: Ding F. , Yuan H. , Wan W. , Reid I. M. , Woithe J. M.
Published: July 2004

This paper presents a 7 year climatology describing medium‐scale gravity waves observed in the menopause region covering the years from 1995 to 2001. The data comes from the OI and OH airglow observations of the three‐field photometer employed at the University of Adelaide's Buckland Park, Australia (34.5°S, 138.5°E). About 1300 gravity wave events (AGW) are identified during the years 1995–2001. These AGW events usually persist for between 40 min and 4 hours. The magnitudes range from 1% to 14% of the background intensities and peak at 2% for OI observations and at 3% for OH observations. The observed periods range from 10 to 30 min, and the horizontal phase speeds range from 20 to 250 m s−1, with dominant wave scales of 17 min, 70 m s−1 for OI observations and 20 min, 40 m s−1 for OH observations. The intrinsic parameters are obtained by using medium‐frequency (MF) wind data observed at the same place. The occurrence frequency of AGW events peaks at 13 min, 40 m s−1 for both OI and OH observations. The occurrence rate of gravity waves has a major peak in summer and a minor peak in winter. There is an obvious dominating southeastward direction for gravity waves, with azimuths of 160° in summer and 130° in winter. Studies for gravity waves observed in various locations show a similar tendency of propagating meridionally toward the summer pole. This implies that the tendency of propagating toward the summer pole may be a global trend for medium‐scale gravity waves observed in the mesopause region. During summer, gravity waves propagate against winds measured by MF radar in their dominating direction. Using the ray tracing method, we found that the seasonal variation of winds limits the access of gravity waves to the observation height through reflection and critical coupling, which is one of the causes leading to the seasonal behavior of gravity waves observed over Adelaide.
Modeling the diurnal variation of nitrate during the Pittsburgh Air Quality Study
Authors: Takahama Satoshi , Wittig Ann E. , Vayenas Dimitris V. , Davidson Cliff I. , Pandis Spyros N.
Published: July 2004

A thermodynamic model, the Gibbs Free‐Energy Minimization model (GFEMN), was used to simulate the partitioning of PM2.5 nitrate aerosol and nitric acid using highly time‐resolved inorganic measurements collected at the Pittsburgh Air Quality Study during July 2001 and January 2002. Model results were evaluated using independent, high time resolution measurements of aerosol nitrate. The mean observed concentration in July was 0.6 μg/m3 and 2.1 μg/m3 in January. Model predictions were in agreement with the observations within 0.5 μg/m3 on average, with measurement uncertainties often accounting for these discrepancies. The simulations were run assuming particles were liquid in July for all relative humidities (RHs) and solid below 60% RH in January. For both seasons the assumed physical state did not influence considerably the overall agreement with observations. The assumption of particle mixing state did appear to influence model error; however, assuming that particles were externally mixed during low RH periods in July improved agreement significantly. The exceptional sensitivity of predicted aerosol nitrate to ammonia in western Pennsylvania suggests that reductions in PM2.5 may be assisted by reductions in ammonia emissions.
Photochemistry, ozone production, and dilution during long‐range transport episodes from Eurasia to the northwest United States
Authors: Price Heather U. , Jaffe Daniel A. , Cooper Owen R. , Doskey Paul V.
Published: July 2004

On the basis of observations from the 1997–2002 Photochemical Ozone Budget of the Northeast Pacific (PHOBEA) experiments, we have identified 11 transpacific long‐range transport (LRT) episodes, which contain significantly elevated levels of CO, O3, and aerosol scattering. The LRT episodes were determined from aircraft and ground‐based observations of CO, O3, aerosol scattering coefficient, and 281 whole air samples analyzed for nonmethane hydrocarbons (NMHC). The ratio of excess O3 to excess CO (ΔO3/ΔCO) for the 11 LRT episodes ranged from −0.06 to 1.52. Lower ΔO3/ΔCO ratios (<0.10) are characteristic of LRT episodes transported in the boundary layer or in the presence of substantial mineral dust. These events lack O3 enhancements, even though O3 precursors (CO, NMHCs) are elevated. Ratios of ΔO3/ΔCO of 0.2–0.5 are characteristic of LRT episodes of industrial and/or biomass burning where excess CO is coincident with expected excesses in O3. High ΔO3/ΔCO ratios (>0.50) are found in LRT episodes transported higher in the free troposphere and are probably due to a mixing of LRT pollution plumes with ozone‐rich upper tropospheric air. Using PHOBEA observations, backward trajectories, and data from other experiments in the North Pacific (TRACE‐P, ACE‐Asia, PEM‐West B) we calculate OH concentrations using two different methods. For the LRT episodes we obtain mean OH concentrations between 1.9 × 105 and 1.3 × 106 molecules cm−3. We also present a method using dispersion models and observations to calculate the rate of dilution, kdil, with background air during LRT. A low kdil indicates less mixing with background air during transport, while a high value represents more entrainment with background air. For the April 2001 LRT episode we calculate a mean kdil of 0.010 ± 0.004 hr−1 and an OH radical concentration of 2 × 105 molecules cm−3. On the basis of these calculations we find that the large mineral dust transport episode, which took place in April 2001, was associated with the lowest OH concentration of the 11 episodes considered, implicating a strong role for heterogeneous chemistry during LRT.
Long‐range transport of Asian pollution to the northeast Pacific: Seasonal variations and transport pathways of carbon monoxide
Authors: Liang Qing , Jaeglé Lyatt , Jaffe Daniel A. , Weiss‐Penzias Peter , Heckman Anna , Snow Julie A.
Published: July 2004

Continuous CO measurements were obtained at Cheeka Peak Observatory (CPO, 48.3°N, 124.6°W, 480 m), a coastal site in Washington state, between 9 March 2001 and 31 May 2002. We analyze these observations as well as CO observations at ground sites throughout the North Pacific using the GEOS‐CHEM global tropospheric chemistry model to examine the seasonal variations of Asian long‐range transport. The model reproduces the observed CO levels, their seasonal cycle and day‐to‐day variability, with a 5–20 ppbv negative bias in winter/spring and 5–10 ppbv positive bias during summer. Asian influence on CO levels in the North Pacific troposphere maximizes during spring and minimizes during summer, ranging from 91 ppbv (44% of total CO) to 52 ppbv (39%) along the Asian Pacific Rim and from 44 ppbv (30%) to 24 ppbv (23%) at CPO. Maximum export of Asian pollution to the western Pacific occurs at 20°–50°N during spring throughout the tropospheric column, shifting to 30°–60°N during summer, mostly in the upper troposphere. The model captures five particularly strong transpacific transport events reaching CPO (four in spring, one in winter) resulting in 20–40 ppbv increases in observed CO levels. Episodic long‐range transport of pollutants from Asia to the NE Pacific occurs throughout the year every 10, 15, and 30 days in the upper, middle, and lower troposphere, respectively. Lifting ahead of cold fronts followed by transport in midlatitude westerlies accounts for 78% of long‐range transport events reaching the NE Pacific middle and upper troposphere. During summer, convective injection into the upper troposphere competes with frontal mechanisms in this export. Most events reaching the NE Pacific lower troposphere below 2 km altitude result from boundary layer outflow behind cold fronts (for spring) or ahead of cold fronts (for other seasons) followed by low‐level transpacific transport.
Gas‐phase chemical characteristics of Asian emission plumes observed during ITCT 2K2 over the eastern North Pacific Ocean
Authors: Nowak J. B. , Parrish D. D. , Neuman J. A. , Holloway J. S. , Cooper O. R. , Ryerson T. B. , Nicks D. K. , Flocke F. , Roberts J. M. , Atlas E. , de Gouw J. A. , Donnelly S. , Dunlea E. , Hübler G. , Huey L. G. , Schauffler S. , Tanner D. J. , Warneke C. , Fehsenfeld F. C.
Published: July 2004

The gas‐phase chemical characteristics of emission plumes transported from Asia across the Pacific Ocean observed during the Intercontinental Transport and Chemical Transformation experiment in 2002 (ITCT 2K2) are described. Plumes measured in the troposphere from an aircraft were separated from the background air in data analysis using 1‐s measurements of carbon monoxide (CO), total reactive nitrogen (NOy), and other gas‐phase species along with back trajectory analysis. On the basis of these measurements, Asian transport plumes with CO mixing ratios greater than 150 ppbv were observed on seven flights. Correlations between 1‐s observations of CO, ozone (O3), and NOy are used to characterize the plumes. The NOy/CO ratios were similar in each plume and significantly lower than those derived from estimated Asian emission ratios, indicating substantial removal of soluble NOy species during transport. Observations of nitric oxide (NO), nitrogen dioxide (NO2), nitric acid (HNO3), peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN), and alkyl nitrates are used with the NOy measurements to further distinguish the transport plumes by their NOy partitioning. NOy was primarily in the form of PAN in plumes that were transported in cold high‐latitude and high‐altitude regions, whereas in plumes transported in warmer, lower latitude and altitude regions, NOy was mainly HNO3. Additional gas‐phase species enhanced in these plumes include sulfuric acid, methanol, acetone, propane, and ethane. The O3/CO ratio varied among the plumes and was affected by the mixing of anthropogenic and stratospheric influences. The complexity of this mixing prevents the determination of the relative contribution of anthropogenic and stratospheric influences to the observed O3 levels.
Decreasing trend in the strength of Tropical Easterly Jet during the Asian summer monsoon season and the number of tropical cyclonic systems over Bay of Bengal
Authors: Rao B. R. Srinivasa , Rao D. V. Bhaskar , Rao V. Brahmananda
Published: July 2004

The NCEP/NCAR reanalysis data during the period 1958–1998 show a positive trend in the 100 hPa zonal wind, decrease in the strength of Tropical Easterly Jet (TEJ) during the summer monsoon period of June through September. This is confirmed by the Radiosonde data. The number of observed Tropical Cyclonic Systems (TCS) over Bay of Bengal during the same period shows a decreasing trend. There is a strong negative correlation (−0.549 for the period 1958–1998, 41 years, significant at 99.9% level by a two sided student t test) between the strength of TEJ and the number of Bay of Bengal TCS. This result has potential for long‐range prediction of TCS, which is vital for the prediction of monsoon rainfall.
The circulation of North Atlantic Deep Water at 16°N, 2000–2003
Authors: Rhein Monika , Walter Maren , Mertens Christian , Steinfeldt Reiner , Kieke Dagmar
Published: July 2004

The circulation of North Atlantic Deep Water (NADW) at 16°N is studied with chlorofluorocarbon (CFC) and current measurements in 2000, 2002 and 2003. The transport of the Deep Western Boundary Current (DWBC) ranges from 25.6 to 28.9 Sv in 2000 and 2002. CFC concentrations in the DWBC increased by ∼30% per year during that period. In 2003, the DWBC was weak and the main CFC increase between 2002 and 2003 occurred offshore of the DWBC. For all three repeats, a major drop in the CFC concentrations of the NADW took place at 55°W. This was also found in the distributions of salinity and oxygen. The region west of 55°W was characterized by a predominantly southward flow. The lowest CFC concentrations were found above the Mid‐Atlantic Ridge, where the zonal and meridional velocities were small and no preference of flow direction could be detected.
A new type of volcano flank failure: The resurgent caldera sector collapse, Ischia, Italy
Authors: Tibaldi Alessandro , Vezzoli Luigina
Published: July 2004

This study is the first description of recurrent and rapid lateral failure of the resurgent portion of a caldera complex. The sliding planes and the characteristics of debris avalanche deposits resemble those of cone sector collapses, but the main triggering mechanism proposed at Ischia caldera (Italy) is related to intermittent resurgence. During the last 33 ka, the increase in resurgence rate produced major collapses southward due to three main mechanisms that contributed to an increase in shear stress: i) magma‐driven uplift, which produced increase in static loading, ii) faulting and associated deformation, which induced tilting and steepening of the original layering, and iii) earthquake shaking due to coseismic faulting. The largest episodes of flank failure occurred in the interval 8.6–5.7 ka BP. These were followed by magma eruption and a decrease in the resurgence rate. Recognition of this phenomenon is particularly important in recent/active calderas located near the coast, as it can trigger tsunamis.
Improving global estimates of atmospheric emissions from biomass burning
Authors: Kasischke Eric S. , Penner Joyce E.
Published: July 2004

Biomass burning during wildland fires is an important source of atmospheric trace gasses and particulate matter. A meeting sponsored by Global Observation of Forest Cover/Global Observation of Land Dynamics and International Geosphere‐Biosphere Program/International Global Atmospheric Chemistry/Biomass Burning Experiment to review the status of efforts using satellite‐based burned‐area products to estimate global emissions from biomass burning was held in July 2002. Here we summarize the results of papers submitted from this meeting and contained in this special section. In addition, the findings and recommendations from the workshop are summarized. While new burned‐area products make it possible to estimate wildland fire emissions at continental and global scales, differences in approaches to quantify fuel loads and combustion factors lead to significant variations in emissions estimates. These differences highlight the need for in‐depth comparisons between emission estimation approaches and further research directed toward integration of research conducted at regional scales into the global‐scale approaches to estimate emissions.
Vibronic Coupling. I. Mathematical Treatment for Two Electronic States
Authors: Fulton Robert L. , Gouterman Martin
Published: July 2004

A general mathematical treatment of vibronic coupling of two electronic states in molecules and dimers is presented. The 2×2 matrix Hamiltonian which is derived is shown to reduce to two one-dimensional Hamiltonians provided a certain minimum amount of symmetry is present. Some general selection rules governing electronic transitions to these states from the ground state are obtained, showing that the spectral distribution in hot bands may differ considerably from that in normal bands when vibronic coupling occurs. A special model which considers the coupling to arise from a single mode of vibration is presented. Two limiting cases which can be treated approximately by perturbation theory are considered in detail. These are shown to give rise to a ``pseudo Jahn-Teller effect'' and to vibrational borrowing in the two different limits.
On the Evaluation of Integrals Occurring in the Theory of the Correlated Electronic Wave Functions
Authors: Szász Levente
Published: July 2004

It can be shown that the simplest generalization of the Hylleraas method for atoms with arbitrary number of electrons leads to integrals of six and nine dimensions, respectively, where the interelectronic distances occur in the integrands. The purpose of the present paper is to show that the nine-dimensional integrals can be treated by a similar procedure to that which was suggested for the evaluation of the six-dimensional integrals by Hylleraas and Breit.
Hyperfine Structure and g-Tensor Anisotropy of the Paramagnetic Resonances of Manganese in TiO2
Authors: Andresen Harro G.
Published: July 2004

Several characteristic resonances of the paramagnetic spectrum of a manganese-doped TiO2 single crystal in its rutile structure were measured with high precision in order to improve the accuracy of the spin Hamiltonian parameters. The measurements were performed at room temperature and at X-band frequencies. Especially, the anisotropy of the g tensor and that of the A tensor were evaluated using the resonance data measured at orientations of the magnetic field parallel to the three magnetic axes of the rutile crystal. The hyperfine structure patterns of the manganese resonances are discussed qualitatively for various crystal orientations; two properly selected |ΔmI|=1 transitions were used to estimate the upper limit of the quadrupole-term parameters of the spin Hamiltonian.

The paramagnetic resonances of manganese in rutile were also investigated at liquid nitrogen temperature and at X-band frequencies. Aside from a spectrum that is very similar to the spectrum already observed at room temperature and assigned to tetravalent manganese atoms, having a spin value of S=32, additional manganese resonances of strong intensity were observed. Though it is very likely that these resonances can be attributed to manganese atoms of a different valence state, the paramagnetic data at X-band frequencies are insufficient to determine the origin of these resonances unambiguously.
Electronic Spectra and Hydrogen Bonding. I. Phenol and Naphthols
Authors: Baba Hiroaki , Suzuki Satoshi
Published: July 2004

The effect of hydrogen bonding on the electronic absorption spectra of phenol, α naphthol, and β naphthol has been investigated with particular attention to the relation between the nature of electronic transitions and their behavior in hydrogen bond formation. The spectra were obtained down to 2000 A in isooctane solution in the presence of varying concentrations of dioxane. From the analysis of the observed spectra, the equilibrium constants for the hydrogen bonds and the spectra of the hydrogen-bonded species were determined. The hydrogen bond energies are given for the ground and excited states of the solute molecules. The experimental results clearly indicate that effects of hydrogen bonding on electronic spectra differ markedly with transitions. Both the frequency shifts and the intensity changes differ in magnitude and even in sign according to the properties of the transitions concerned. It is shown that the transition at 47 000 cm−1 of α naphthol is displaced to higher frequencies upon formation of the hydrogen bond. No appreciable changes are produced by hydrogen bonding in the spectral patterns of the individual transitions, aside from broadening or smoothing of the vibrational structure. The behavior of the transitions in hydrogen bond formation is interpreted on the basis of the electronic structure of the solute molecules. Two factors are shown to be important for accounting for the mechanism of the hydrogen bonding effect: (a) a change in the electron density at the oxygen atom of the O–H group accompanying an electronic transition; (b) a decrease in the electronegativity of the same oxygen atom resulting from hydrogen bond formation.
Self-Nucleation in the Sulfuric Acid-Water System
Authors: Doyle George J.
Published: July 2004

Howard Reiss' ``Vector model'' was adapted to calculate the self-nucleation rate for the sulfuric acid-water system and similar systems.

A numerical calculation was carried out for the typical case of 50% relative humidity at 25°C. It was concluded that rapid self-nucleation would take place at sulfuric acid partial pressures in the range 10-8-10-10 mm Hg. The considerable uncertainty is principally due to lack of data on the partial pressure of sulfuric acid above its aqueous solutions and on the dominant sulfuric acid-bearing species in humid atmospheres.
Electrical Conductivity of Synthetic Crystalline Zeolites
Authors: Freeman Donald C. , Stamires Dennis N.
Published: July 2004

The electrical conductivity of anhydrous Linde zeolite types A, X, and Y in various cationic forms has been measured between 20 and 400°C. The conductivity is ohmic, essentially noncapacitive, and appears to be strictly ionic with unusually low activation energy. From the effect of zeolite channel size, type of cation and cation density on ΔH, ΔG, and ΔS for the conduction process, some conclusions as to the zeolite internal structure and surface energy have been obtained. The heterogeneity of the internal surface energy found by the measurement of adsorption heats is discussed in the light of these conclusions.
Least-Squares Local-Energy Method for Molecular Energy Calculations Using Gauss Quadrature Points
Authors: Frost A. A. , Kellogg R. E. , Gimarc B. M. , Scargle J. D.
Published: July 2004

The least-squares local-energy method previously described and tested in calculations on H2+ has been further tested on H2+, He, and H2. The theory of Gauss quadrature is used to provide a better basis of points over which to average the local-energy. The electronic energy is easily calculated to six significant figures for H2+ and to three or four significant figures for He and H2.
Electron Coupling of Proton Spins in Heterocyclic Molecules. N-benzylthieno[3,2-b]pyrrole
Authors: Gutowsky H. S. , Porte A. L.
Published: July 2004

The high-resolution proton magnetic resonance spectrum of the four protons attached to the heterocyclic rings of N-benzylthieno[3,2-b]pyrrole (I) has been examined in detail at 16.2 Mc/sec. The spectrum is of the type ABCD perturbed by two nuclei X2 which couple with A, and it involves three long-range proton-proton couplings, 0.5, 1.3, and 0.3 cps over five, six, and six bonds, respectively, which can be accounted for only by pi-electron interactions. The analysis of the spectrum indicates that all of the coupling constants have the same sign, which is presumed to be positive on theoretical grounds. This analysis illustrates the great value of obtaining unambiguous magnitudes of the coupling constants and chemical shifts from high-frequency spectra in order to determine the relative signs of the coupling constants from low-frequency spectra. The coupling constants found in each of the rings in I are compared with those of the monocyclic compounds, thiophene and pyrrole. Although angular effects may govern the coupling via sigma electrons in HCCH groups, the pi-electron contribution appears to be sensitive to electronegativity differences. In addition, heteroatoms and ionic structures are important in determining the long-range coupling via the pi electrons.
Multilayer Adsorption of Helium on Argon
Authors: Ross Marvin , Steele William A.
Published: July 2004

Multilayer isotherms and heats are reported for helium adsorbed on an argon surface at 4.2°K. The data show that, on the uniform surface used in this work, the layer capacities and energies of the first two or three layers of adsorbed helium can be estimated directly from the heats without recourse to the isotherm data. The adsorption energies are shown to be in good agreement with theoretical estimates. Two alternate approaches to the theoretical calculation of layer capacity are presented: one of the methods involves a computation of the perturbation of the density of the bulk liquid due to the presence of the surface; the other calculation is based on a computation of the density dependence of the lateral interaction energy in a layer plus the surface interaction energy of the layer. The density of a completed layer can be estimated by equating the total energies per atom in successive layers. It is shown that the results of these calculations are in good agreement with each other, and with the experiments. The high coverage isotherm data are analyzed in terms of a modified form of the Frenkel-Halsey-Hill isotherm equation, and it is shown that the parameters required to fit the experiments to this equation are consistent with other estimates. Finally, the data are fitted to the B.E.T. equation, and to several of the modified B.E.T. isotherms which have been suggested as more realistic representations of helium adsorption data. It is concluded that no B.E.T.-type model is completely successful, but that the isotherm equation proposed by Steele gives the most accurate results.
Interaction of Rare Gases with Semiconductor Surfaces
Authors: Green Mino , Seiwatz Ruth
Published: July 2004

The interaction of krypton with clean germanium surfaces has been analyzed in terms of dispersion forces, assuming a 6:12 potential. Using the experimental value for the heat of adsorption and a computed value for the attractive term in the 6:12 potential, the repulsive term in the potential was calculated. The interaction energy at various positions on the (111) crystal plane of germanium was then computed. The method used involves recently developed techniques for the summation over a semi-infinite crystal. From this analysis an effective van der Waals radius for the surface germanium atoms can be deduced, and the value (1.8 A) seems to be, from several points of view, physically reasonable. Using an empirical combination rule, it is then possible to predict heats of adsorption for other germanium-rare gas systems, viz., (Ge–Ar) 3.3 kcal/mole; (Ge–Xe) 4.1 kcal/mole.

The contribution of the induction effect to the heat of adsorption at various positions on the (111) plane has been calculated for a specific model, and the results show that while there is a significant contribution, roughly 0.8 kcal/mole, the dominant adsorption force is the dispersion interaction. The possible contribution of surface heterogeneity to the heat of adsorption is discussed in terms of adsorption at a surface step. A description of the method of summation over the semi-infinite crystal is dealt with in an Appendix.
Infrared Spectrum of Solid Carbon Monoxide
Authors: Ewing George E. , Pimentel George C.
Published: July 2004

The infrared spectrum of solid carbon monoxide at 20°K has been examined in the fundamental and overtone regions. Sharp features (bandwidths about one cm−1) are assigned to vibrational modes of the various isotopic species: C12O16, 2138.1 cm−1; C12O17, 2112.3 cm−1; C13O16, 2092.2 cm−1; and C12O18, 2088.4 cm−1. These frequencies are examined with the aid of existing theories of frequency shifts in condensed phases. A broad absorption (bandwidth about 40 cm−1) centered at 2208 cm−1 is assigned to combinations of the fundamental mode with lattice modes. Calculations suggest that the lattice modes involved probably include translations as well as librations.
Studies of the Optical and Infrared Absorption Spectra of Rutile Single Crystals
Authors: Soffer Bernard H.
Published: July 2004

The optical absorption of single crystals of synthetic rutile was investigated in the spectral range 1200 to 25 000 cm−1 from room temperature to 1000°C. The electronic absorption exhibits dichroic behavior. The edge moves toward lower energies as temperature is increased, with the shift depending upon the absorption coefficient; for a decadic absorption coefficient α′ of 400 cm−1, the shift is −7.1×10−4 ev/°K, while at 1 cm−1 it is −9.5×10−4 ev/°K. The broad band in the region of 6850 cm−1 which occurs in reduced rutile does not appear in fully oxidized rutile, even at high temperatures. At high temperatures an additional wavelength-independent absorption appears which can be correlated in good agreement with dc conductivity by applying the Drude-Zener theory of free carrier absorption. New bands in the 3300 cm−1 region are shown to stem from O–H valence vibrations. The main bands are unusually sharp, with peaks at 3277 and 3322 cm−1 and half-widths of 28 and 13 cm−1. A satellite structure of combination and difference bands was also detected. Deuterium substitution produces an absorption band at 2442 cm−1. The entire structure shows a marked dependence of the absorption on the polarization direction of the light. Some evidence is presented that these O–H groups cause a dielectric dispersion.
Molecular Weight Distribution from the Normal Coordinate Theory of Viscoelasticity
Authors: Menefee Emory , Peticolas Warner L.
Published: July 2004

The normal coordinate theory of viscoelasticity has been shown to provide a bridge between the measurable rheological properties of linear polymers and their molecular weight distribution functions, as well as their average molecular weights. Equations have been derived relating the molecular weight distribution function of a linear polymer to a sum of functions of a measurable rheological property such as stress relaxation or dynamic viscosity. Thus, a method for the simple and rapid determination of molecular weight distribution has been developed within the limitations of the normal coordinate theory.
Dipole Moment of HD. II
Authors: Blinder S. M.
Published: July 2004

The permanent electric dipole moment in the ground vibrational state of HD is computed by a variational technique (generalized perturbation method). Implicit account is thereby taken of contributions from higher molecular states of 1Σu+ symmetry. The value 〈μZ〉v=0=5.67×10−4 Debye unit is assigned. Factors affecting the accuracy of the computation are discussed in detail. It is shown that an effective dipole moment function may be defined despite the fact that the dipole arises from a vibrational-electronic interaction.
Diamond-Graphite Equilibrium Line from Growth and Graphitization of Diamond
Authors: Bundy F. P. , Bovenkerk H. P. , Strong H. M. , Wentorf R. H.
Published: July 2004

Diamond growth occurs at high temperatures and pressures in the presence of certain molten metals which serve as solvent catalysts. The zones of pressure and temperature in which diamond growth occurs have been determined for a number of metals. These zones are bounded on the low-temperature side by the melting point of the metal-carbon eutectic at pressure. They are bounded on the high-temperature side by the diamond-graphite equilibrium line. This experimentally determined equilibrium line agrees very closely with the theoretical extrapolation of the thermodynamically calculated line proposed by Berman and Simon, viz., P(kbar)=7.1+0.027T(∘K).
Effect of Pressure on the Spectrum of Ruby
Authors: Stephens D. R. , Drickamer H. G.
Published: July 2004

The effect of pressure has been measured on the spectrum of ruby, both parallel and perpendicular to the C axis, to 120 kbar. From these data it is possible to calculate the change in crystal field strength Dq in interelectronic repulsion B and in trigonal field distortion (−32K). The crystal field increases with increasing pressure, while the interelectronic repulsion decreases, indicating increasing covalency. The trigonal distortion is constant to about 60 kbar, and then increases markedly at higher pressures. The fractional change in Dq with pressure follows the R-5 law closely to 30 kbar, the upper limit of the p-v data.
Effect of Pressure on Tetrahedral Ni++ and Co++ Complexes
Authors: Stephens D. R. , Drickamer H. G.
Published: July 2004

The effect of pressure has been studied on the spectra of five tetrahedral Co++ complexes and two tetrahedral Ni++ complexes. Calculations have been made for the change in the crystal-field parameter 10 Dq and for the change in the interelectronic repulsion B. The increase in 10 Dq and the decrease in B correlates strongly with the polarizibility of the ligands. For the Co++ complexes the effect of pressure on the spin-orbital splitting was studied. The splitting increased with pressure to an extent determined by the mass and polarizability of the ligand. For ZnS compressibility data were available. It was found that the fractional change in Dq for both Co++ and Ni++ was greater than that predicted from the bulk compressibility of ZnS. This is attributed to relaxation in the neighborhood of the foreign ion.
Energy Value of the Octahedral-Tetrahedral Coordination Change
Authors: Katzin Leonard I.
Published: July 2004

The equilibrium oct(CoCl2Py4) = tet(CoCl2Py2) +2Py for cobaltous chloride solutions in pyridine is followed over a temperature range, yielding ΔH = +13.4 kcal/mole. At 38°C the equilibrium constant is estimated as (CoPy2Cl2) (Py)2/(CoCl2Py4) = 0.04, and the ΔS for the reaction is about 36.7 eu. It is pointed out that the average bond strength in the tetrahedral species is about 17 kcal greater than for the same groups in the octahedral configuration, and that the strength of binding and the dissociation energy for the two ligands released according to the equation above are significant factors in determining the equilibrium reaction.

Detailed arguments are given against the view that the relative stability of octahedrally and tetrahedrally coordinated complexes, such as the pair discussed, reflect principally the difference in ``ligand-field stabilization'' of the nonbonding d electrons between octahedral and tetrahedral fields.
Molecular Detachment Processes in the Vacuum uv Photolysis of Gaseous Hydrocarbons. I. Ethylene. II. Butane
Authors: Sauer Myran C. , Dorfman Leon M.
Published: July 2004

The photolysis of ethylene and of butane has been studied at room temperature with light of 1470 A. The results of isotopic studies, along with a detailed examination of the products of reaction, establish conclusively that molecular detachment processes are of major importance in the primary decomposition of the photoexcited states formed.

In the photolysis of ethylene at 1470 A the primary processes are C2H4*=C2H2+H2φ1C2H4**=C2H2+2Hφ2with φ1≅φ2. Rupture of only a single carbon-hydrogen bond is not an important primary process. The foregoing reactions, along with the subsequent interactions of ethyl radicals, formed by hydrogen atom addition to ethylene, furnish a unique description of almost all the photochemistry observed under the conditions of the experiments.

In the photolysis of butane at 1470 A, molecular detachment of hydrogen: C4H10*=C4H8+H2is a major primary process. The detailed nature of any other primary reactions has not been established.
q-Dimensional Excluded Volume in Random Flight Chains
Authors: von Frankenberg Carl , Hughes R. E.
Published: July 2004

The dependence of 〈r2〉 on the number of links in a random flight chain is calculated for an arbitrary number of dimensions from generalizations of the treatments of James and Fixman. The results are compared with those from other approaches. The extension of the James theory to include second-order corrections is briefly discussed.
Intramolecular Charge Transfer in Aromatic Free Radicals
Authors: McConnell Harden M.
Published: July 2004

A theoretical analysis is made of the rate of intramolecular transfer of the odd electron between the two phenyl groups in the mononegative ions of the α,ω-diphenyalkanes, φ—(CH2)n—φ. The essential features of the calculations are: (a) It is shown that the polymethylene chain can be replaced by a pseudopotential corresponding to an effective direct transfer between the rings. (b) There is a strong tendency for self-trapping of the odd electron on one phenyl ring, or the other, due to solvent polarization and bond distortions in the rings. This self-trapping greatly reduces the rate of intramolecular charge transfer. (c) The intramolecular charge transfer occurs as an electronic resonance effect when a short-lived thermally activated molecular state is formed in which the two rings appear to the odd electron to be equivalent to one another. The activation energy is estimated to be of the order of 1000 cm—1. (d) It is found that the rate of intramolecular charge transfer decreases exponentially with the length of the polymethylene chain, the decrease being as much or more than a factor of ten for each added methylene group.
Comprehensive Investigation of the Electronic Spectroscopy and Theoretical Treatments of Ferrocene and Nickelocene
Authors: Scott Donald R. , Becker Ralph S.
Published: July 2004

New data concerning the electronic absorption and emission spectra of ferrocene and the absorption spectrum of nickelocene are presented. Assignment and discussion of the transitions are made based on the experimental results. No ferrocene emission is observed upon excitation into the lowest energy absorption band. An emission occurs upon excitation into the next higher energy band. These results are interpreted in terms of crossing of the first excited state and the ground state. The luminescence is long lived and is interpreted as phosphorescence paralleling an assigned singlet-triplet absorption at 5280 A. No nickelocene emission was noted. Assignments of the absorption bands of ferrocene and nickelocene are proposed within the framework of each of the major theoretical approaches.
Faraday Effect in Molecules
Authors: Tobias Irwin , Kauzmann Walter
Published: July 2004

The relationship between the measured Verdet constants of a number of molecules and the quantum-mechanical theory of the Faraday effect is examined. The observed behavior of nitric oxide, which is significantly different from that of the diamagnetic gases, is explained by a consideration of the effect on the Verdet constant of the transition from the Π12 state to the 2Σ state lying at 44 000 cm—1.