cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.963375
title: The ro-vibrational analysis of the <i>v</i><sub>4</sub> fundamental band of CF<sub>3</sub>Br from jet-cooled diode laser and FTIR spectra in the 8.3-μm region

description: The <i>v</i><sub>4</sub> fundamental band of CF<sub>3</sub><sup>79</sup>Br and CF<sub>3</sub><sup>81</sup>Br, present in natural isotopic abundance, was investigated in the 8.3-μm region by high-resolution infrared spectroscopic techniques. Tuneable diode laser spectra were recorded in the ranges 1202.5–1205.0 cm<sup>−1</sup>, 1208.0–1210.1 cm<sup>−1</sup> and 1212.5–1214.5 cm<sup>−1</sup>. The tuneable diode laser spectra were obtained at the reduced temperature of 200 K and in a free-jet expansion. The latter technique was used to reduce spectral congestion, achieving a rotational temperature of about 50 K, with a resolution up to 0.0008 cm<sup>−1</sup>. A Fourier transform infrared spectrum covering the entire spectral region of the <i>v</i><sub>4</sub> band, between 1190 and 1220 cm<sup>−1</sup>, was recorded at 298 K with a resolution of 0.004 cm<sup>−1</sup>. The experimental wavenumbers from the different spectroscopic techniques were combined to accomplish the complete ro-vibrational analysis of <i>v</i><sub>4</sub>. In total, 4651 transitions were assigned to CF<sub>3</sub><sup>79</sup>Br, 4047 to CF<sub>3</sub><sup>81</sup>Br, with <i>J</i>″<sub>max </sub> = <i>K</i>″<sub>max </sub>=80; of these, 3171 for CF<sub>3</sub><sup>79</sup>Br and 2755 for CF<sub>3</sub><sup>81</sup>Br are from diode laser measurements. The data of each isotopologue were analysed using the model Hamiltonian for a degenerate vibrational state of a molecule of <i>C</i><sub>3</sub><sub><i>v</i></sub> symmetry. The <i>v</i><sub>4</sub> band of both the isotopologues resulted essentially unperturbed, but the Δ<i>l</i> = Δ<i>k</i> = ±2 <i>l</i>-resonance was found to be active within the <i>v</i><sub>4</sub> = 1 state. Precise values of the vibrational energy and of the ro-vibrational parameters of <i>v</i><sub>4</sub> = 1 for CF<sub>3</sub><sup>79</sup>Br and CF<sub>3</sub><sup>81</sup>Br were obtained. The bromine isotopic splitting amounts to 6.9 × 10<sup>−3</sup> cm<sup>−1</sup>. In addition, the equilibrium geometry and the harmonic force field were calculated <i>ab initio</i> using the large-size basis set def2-QZVP in conjunction to the PBE0 functional.
DOI: 10.6084/m9.figshare.963378.v1
title: Density-fitted singles and doubles coupled cluster on graphics processing units

description: We adapt an algorithm for singles and doubles coupled cluster (CCSD) that uses density fitting or Cholesky decomposition (CD) in the construction and contraction of all electron repulsion integrals (ERIs) for use on heterogeneous compute nodes consisting of a multicore central processing unit (CPU) and at least one graphics processing unit (GPU). The use of approximate three-index ERIs ameliorates two of the major difficulties in designing scientific algorithms for GPUs: (1) the extremely limited global memory on the devices and (2) the overhead associated with data motion across the bus. For the benzene trimer described by an aug-cc-pVDZ basis set, the use of a single NVIDIA Tesla C2070 (Fermi) GPU accelerates a CD-CCSD computation by a factor of 2.1, relative to the multicore CPU-only algorithm that uses six highly efficient Intel Core i7-3930K CPU cores. The use of two Fermi GPUs provides an acceleration of 2.89, which is comparable to that observed when using a single NVIDIA Kepler K20c GPU (2.73).
DOI: 10.6084/m9.figshare.963376.v2
title: Similarity transformed equation of motion coupled cluster theory revisited: a benchmark study of valence excited states

description: The similarity transformed equation of motion coupled cluster (STEOM-CC) method is benchmarked against CC3 and EOM-CCSDT-3 for a large test set of valence excited states of organic molecules studied by Schreiber et al. [M. Schreiber, M.R. Silva-Junior, S.P. Sauer, and W. Thiel, J. Chem. Phys. <b>128</b>, 134110 (2008)]. STEOM-CC is found to behave quite satisfactorily and provides significant improvement over EOM-CCSD, CASPT2 and NEVPT2 for singlet excited states, lowering standard deviations of these methods by almost a factor of 2. Triplet excited states are found to be described less accurately, however. Besides the parent version of STEOM-CC, additional variations are considered. STEOM-D includes a perturbative correction from doubly excited determinants. The novel STEOM-H (ω) approach presents a sophisticated technique to render the STEOM-CC transformed Hamiltonian hermitian. In STEOM-PT, the expensive CCSD step is replaced by many-body second-order perturbation theory (MBPT(2)), while extended STEOM (EXT-STEOM) provides access to doubly excited states. To study orbital invariance in STEOM, we investigate orbital rotation in the STEOM-ORB approach. Comparison of theses variations of STEOM for the large test set provides a comprehensive statistical basis to gauge the usefulness of these approaches.
DOI: 10.6084/m9.figshare.963374
title: The dynamics of colloidal intrusions in liquid crystals: a simulation perspective

description: Dispersing colloidal particles into liquid crystals provides a promising avenue to build a novel class of materials, with potential applications, among others, as photonic crystals, biosensors, metamaterials and new generation liquid crystal devices. Understanding the physics and dynamical properties of such composite materials is then of high-technological relevance; it also provides a remarkable challenge from a fundamental science point of view due to the intricacies of the hydrodynamic equations governing their dynamical evolution. Here, we provide an overview of our current theoretical understanding of the dynamical and hydrodynamic properties of colloid–liquid crystal composites, focussing on the results obtained from computer simulations; no or very limited previous knowledge of the field of liquid crystals is assumed. While our main emphasis is on the dynamics, we also review a selection of equilibrium results and simulations to provide the necessary background. We start by describing what we know about the simplest possible problem: that of a single particle in a nematic, or cholesteric, liquid crystal. We then consider two particles, and review the conditions which lead to the formation of a dimer; we then again focus on dynamical problems. Finally, we turn to the more complicated case of a dispersion, reviewing here simulations motivated by optical tweezer and rheological experiments. We close by making a list of some of the many open problems in this rapidly developing research field.
DOI: 10.6084/m9.figshare.963377.v2
title: The eight-valence-electron systems re-examined: convergence of the coupled-cluster series and performance of quasiperturbative methods for quadruple excitations

description: We present the results of a coupled-cluster basis-set convergence study on 12 eight-valence-electron systems. These small systems span a wide range of correlation character (from purely dynamical correlation to pathological static correlation) as well as of chemical bonding (from ionic with some backdonation to quadruple covalent bonding). Indicators such as the correlation entropy and the CASSCF 1-C<sub>0</sub><sup>2</sup>, which primarily sample type A static correlation, are good predictors for the energetic importance of connected quintuple excitations, T<sub>5</sub>, and to a lesser extent of higher order triple excitations, T<sub>3</sub>–(T). The percentage of the total atomisation energy recovered by connected triple excitations, %TAE[(T)], is however a fair predictor for the importance of connected quadruples, T<sub>4</sub>. Of the various ansätze for quasiperturbative connected quadruples, CCSDT(Q)/B appears to be the most robust, even as it is still outperformed by the much more expensive CCSDT(Q)<sub>Λ</sub>.
DOI: 10.6084/m9.figshare.963376.v1
title: Similarity transformed equation of motion coupled cluster theory revisited: a benchmark study of valence excited states

description: The similarity transformed equation of motion coupled cluster (STEOM-CC) method is benchmarked against CC3 and EOM-CCSDT-3 for a large test set of valence excited states of organic molecules studied by Schreiber et al. [M. Schreiber, M.R. Silva-Junior, S.P. Sauer, and W. Thiel, J. Chem. Phys. <b>128</b>, 134110 (2008)]. STEOM-CC is found to behave quite satisfactorily and provides significant improvement over EOM-CCSD, CASPT2 and NEVPT2 for singlet excited states, lowering standard deviations of these methods by almost a factor of 2. Triplet excited states are found to be described less accurately, however. Besides the parent version of STEOM-CC, additional variations are considered. STEOM-D includes a perturbative correction from doubly excited determinants. The novel STEOM-H (ω) approach presents a sophisticated technique to render the STEOM-CC transformed Hamiltonian hermitian. In STEOM-PT, the expensive CCSD step is replaced by many-body second-order perturbation theory (MBPT(2)), while extended STEOM (EXT-STEOM) provides access to doubly excited states. To study orbital invariance in STEOM, we investigate orbital rotation in the STEOM-ORB approach. Comparison of theses variations of STEOM for the large test set provides a comprehensive statistical basis to gauge the usefulness of these approaches.
DOI: 10.6084/m9.figshare.963377.v1
title: The eight-valence-electron systems re-examined: convergence of the coupled-cluster series and performance of quasiperturbative methods for quadruple excitations

description: We present the results of a coupled-cluster basis-set convergence study on 12 eight-valence-electron systems. These small systems span a wide range of correlation character (from purely dynamical correlation to pathological static correlation) as well as of chemical bonding (from ionic with some backdonation to quadruple covalent bonding). Indicators such as the correlation entropy and the CASSCF 1-C<sub>0</sub><sup>2</sup>, which primarily sample type A static correlation, are good predictors for the energetic importance of connected quintuple excitations, T<sub>5</sub>, and to a lesser extent of higher order triple excitations, T<sub>3</sub>–(T). The percentage of the total atomisation energy recovered by connected triple excitations, %TAE[(T)], is however a fair predictor for the importance of connected quadruples, T<sub>4</sub>. Of the various ansätze for quasiperturbative connected quadruples, CCSDT(Q)/B appears to be the most robust, even as it is still outperformed by the much more expensive CCSDT(Q)<sub>Λ</sub>.
DOI: 10.6084/m9.figshare.963375.v1
title: The ro-vibrational analysis of the <i>v</i><sub>4</sub> fundamental band of CF<sub>3</sub>Br from jet-cooled diode laser and FTIR spectra in the 8.3-μm region

description: The <i>v</i><sub>4</sub> fundamental band of CF<sub>3</sub><sup>79</sup>Br and CF<sub>3</sub><sup>81</sup>Br, present in natural isotopic abundance, was investigated in the 8.3-μm region by high-resolution infrared spectroscopic techniques. Tuneable diode laser spectra were recorded in the ranges 1202.5–1205.0 cm<sup>−1</sup>, 1208.0–1210.1 cm<sup>−1</sup> and 1212.5–1214.5 cm<sup>−1</sup>. The tuneable diode laser spectra were obtained at the reduced temperature of 200 K and in a free-jet expansion. The latter technique was used to reduce spectral congestion, achieving a rotational temperature of about 50 K, with a resolution up to 0.0008 cm<sup>−1</sup>. A Fourier transform infrared spectrum covering the entire spectral region of the <i>v</i><sub>4</sub> band, between 1190 and 1220 cm<sup>−1</sup>, was recorded at 298 K with a resolution of 0.004 cm<sup>−1</sup>. The experimental wavenumbers from the different spectroscopic techniques were combined to accomplish the complete ro-vibrational analysis of <i>v</i><sub>4</sub>. In total, 4651 transitions were assigned to CF<sub>3</sub><sup>79</sup>Br, 4047 to CF<sub>3</sub><sup>81</sup>Br, with <i>J</i>′′<sub>max </sub> = <i>K</i>′′<sub>max </sub>=80; of these, 3171 for CF<sub>3</sub><sup>79</sup>Br and 2755 for CF<sub>3</sub><sup>81</sup>Br are from diode laser measurements. The data of each isotopologue were analysed using the model Hamiltonian for a degenerate vibrational state of a molecule of <i>C</i><sub>3</sub><sub><i>v</i></sub> symmetry. The <i>v</i><sub>4</sub> band of both the isotopologues resulted essentially unperturbed, but the Δ<i>l</i> = Δ<i>k</i> = ±2 <i>l</i>-resonance was found to be active within the <i>v</i><sub>4</sub> = 1 state. Precise values of the vibrational energy and of the ro-vibrational parameters of <i>v</i><sub>4</sub> = 1 for CF<sub>3</sub><sup>79</sup>Br and CF<sub>3</sub><sup>81</sup>Br were obtained. The bromine isotopic splitting amounts to 6.9 × 10<sup>−3</sup> cm<sup>−1</sup>. In addition, the equilibrium geometry and the harmonic force field were calculated <i>ab initio</i> using the large-size basis set def2-QZVP in conjunction to the PBE0 functional.
DOI: 10.6084/m9.figshare.963375.v3
title: The ro-vibrational analysis of the <i>v</i><sub>4</sub> fundamental band of CF<sub>3</sub>Br from jet-cooled diode laser and FTIR spectra in the 8.3-μm region

description: The <i>v</i><sub>4</sub> fundamental band of CF<sub>3</sub><sup>79</sup>Br and CF<sub>3</sub><sup>81</sup>Br, present in natural isotopic abundance, was investigated in the 8.3-μm region by high-resolution infrared spectroscopic techniques. Tuneable diode laser spectra were recorded in the ranges 1202.5–1205.0 cm<sup>−1</sup>, 1208.0–1210.1 cm<sup>−1</sup> and 1212.5–1214.5 cm<sup>−1</sup>. The tuneable diode laser spectra were obtained at the reduced temperature of 200 K and in a free-jet expansion. The latter technique was used to reduce spectral congestion, achieving a rotational temperature of about 50 K, with a resolution up to 0.0008 cm<sup>−1</sup>. A Fourier transform infrared spectrum covering the entire spectral region of the <i>v</i><sub>4</sub> band, between 1190 and 1220 cm<sup>−1</sup>, was recorded at 298 K with a resolution of 0.004 cm<sup>−1</sup>. The experimental wavenumbers from the different spectroscopic techniques were combined to accomplish the complete ro-vibrational analysis of <i>v</i><sub>4</sub>. In total, 4651 transitions were assigned to CF<sub>3</sub><sup>79</sup>Br, 4047 to CF<sub>3</sub><sup>81</sup>Br, with <i>J</i>″<sub>max </sub> = <i>K</i>″<sub>max </sub>=80; of these, 3171 for CF<sub>3</sub><sup>79</sup>Br and 2755 for CF<sub>3</sub><sup>81</sup>Br are from diode laser measurements. The data of each isotopologue were analysed using the model Hamiltonian for a degenerate vibrational state of a molecule of <i>C</i><sub>3</sub><sub><i>v</i></sub> symmetry. The <i>v</i><sub>4</sub> band of both the isotopologues resulted essentially unperturbed, but the Δ<i>l</i> = Δ<i>k</i> = ±2 <i>l</i>-resonance was found to be active within the <i>v</i><sub>4</sub> = 1 state. Precise values of the vibrational energy and of the ro-vibrational parameters of <i>v</i><sub>4</sub> = 1 for CF<sub>3</sub><sup>79</sup>Br and CF<sub>3</sub><sup>81</sup>Br were obtained. The bromine isotopic splitting amounts to 6.9 × 10<sup>−3</sup> cm<sup>−1</sup>. In addition, the equilibrium geometry and the harmonic force field were calculated <i>ab initio</i> using the large-size basis set def2-QZVP in conjunction to the PBE0 functional.
DOI: 10.6084/m9.figshare.963374.v2
title: The dynamics of colloidal intrusions in liquid crystals: a simulation perspective

description: Dispersing colloidal particles into liquid crystals provides a promising avenue to build a novel class of materials, with potential applications, among others, as photonic crystals, biosensors, metamaterials and new generation liquid crystal devices. Understanding the physics and dynamical properties of such composite materials is then of high-technological relevance; it also provides a remarkable challenge from a fundamental science point of view due to the intricacies of the hydrodynamic equations governing their dynamical evolution. Here, we provide an overview of our current theoretical understanding of the dynamical and hydrodynamic properties of colloid–liquid crystal composites, focussing on the results obtained from computer simulations; no or very limited previous knowledge of the field of liquid crystals is assumed. While our main emphasis is on the dynamics, we also review a selection of equilibrium results and simulations to provide the necessary background. We start by describing what we know about the simplest possible problem: that of a single particle in a nematic, or cholesteric, liquid crystal. We then consider two particles, and review the conditions which lead to the formation of a dimer; we then again focus on dynamical problems. Finally, we turn to the more complicated case of a dispersion, reviewing here simulations motivated by optical tweezer and rheological experiments. We close by making a list of some of the many open problems in this rapidly developing research field.
DOI: 10.6084/m9.figshare.963374.v1
title: The dynamics of colloidal intrusions in liquid crystals: a simulation perspective

description: Dispersing colloidal particles into liquid crystals provides a promising avenue to build a novel class of materials, with potential applications, among others, as photonic crystals, biosensors, metamaterials and new generation liquid crystal devices. Understanding the physics and dynamical properties of such composite materials is then of high-technological relevance; it also provides a remarkable challenge from a fundamental science point of view due to the intricacies of the hydrodynamic equations governing their dynamical evolution. Here, we provide an overview of our current theoretical understanding of the dynamical and hydrodynamic properties of colloid–liquid crystal composites, focussing on the results obtained from computer simulations; no or very limited previous knowledge of the field of liquid crystals is assumed. While our main emphasis is on the dynamics, we also review a selection of equilibrium results and simulations to provide the necessary background. We start by describing what we know about the simplest possible problem: that of a single particle in a nematic, or cholesteric, liquid crystal. We then consider two particles, and review the conditions which lead to the formation of a dimer; we then again focus on dynamical problems. Finally, we turn to the more complicated case of a dispersion, reviewing here simulations motivated by optical tweezer and rheological experiments. We close by making a list of some of the many open problems in this rapidly developing research field.
DOI: 10.6084/m9.figshare.963375.v2
title: The ro-vibrational analysis of the <i>v</i><sub>4</sub> fundamental band of CF<sub>3</sub>Br from jet-cooled diode laser and FTIR spectra in the 8.3-μm region

description: The <i>v</i><sub>4</sub> fundamental band of CF<sub>3</sub><sup>79</sup>Br and CF<sub>3</sub><sup>81</sup>Br, present in natural isotopic abundance, was investigated in the 8.3-μm region by high-resolution infrared spectroscopic techniques. Tuneable diode laser spectra were recorded in the ranges 1202.5–1205.0 cm<sup>−1</sup>, 1208.0–1210.1 cm<sup>−1</sup> and 1212.5–1214.5 cm<sup>−1</sup>. The tuneable diode laser spectra were obtained at the reduced temperature of 200 K and in a free-jet expansion. The latter technique was used to reduce spectral congestion, achieving a rotational temperature of about 50 K, with a resolution up to 0.0008 cm<sup>−1</sup>. A Fourier transform infrared spectrum covering the entire spectral region of the <i>v</i><sub>4</sub> band, between 1190 and 1220 cm<sup>−1</sup>, was recorded at 298 K with a resolution of 0.004 cm<sup>−1</sup>. The experimental wavenumbers from the different spectroscopic techniques were combined to accomplish the complete ro-vibrational analysis of <i>v</i><sub>4</sub>. In total, 4651 transitions were assigned to CF<sub>3</sub><sup>79</sup>Br, 4047 to CF<sub>3</sub><sup>81</sup>Br, with <i>J</i>″<sub>max </sub> = <i>K</i>″<sub>max </sub>=80; of these, 3171 for CF<sub>3</sub><sup>79</sup>Br and 2755 for CF<sub>3</sub><sup>81</sup>Br are from diode laser measurements. The data of each isotopologue were analysed using the model Hamiltonian for a degenerate vibrational state of a molecule of <i>C</i><sub>3</sub><sub><i>v</i></sub> symmetry. The <i>v</i><sub>4</sub> band of both the isotopologues resulted essentially unperturbed, but the Δ<i>l</i> = Δ<i>k</i> = ±2 <i>l</i>-resonance was found to be active within the <i>v</i><sub>4</sub> = 1 state. Precise values of the vibrational energy and of the ro-vibrational parameters of <i>v</i><sub>4</sub> = 1 for CF<sub>3</sub><sup>79</sup>Br and CF<sub>3</sub><sup>81</sup>Br were obtained. The bromine isotopic splitting amounts to 6.9 × 10<sup>−3</sup> cm<sup>−1</sup>. In addition, the equilibrium geometry and the harmonic force field were calculated <i>ab initio</i> using the large-size basis set def2-QZVP in conjunction to the PBE0 functional.
DOI: 10.6084/m9.figshare.963342
title: First cranial remains of <i>Cheirogaster richardi</i> (Testudines: Testudinidae) from the Late Miocene of Ecoparc de Can Mata (Vallès-Penedès Basin, NE Iberian Peninsula): taxonomic and phylogenetic implications

description: Although skulls of extinct Testudinidae are generally much scarcer than shell remains, when available they provide important data for resolving taxonomic and phylogenetic problems, as illustrated here by two well-preserved giant tortoise skulls from the early Vallesian (MN9, Late Miocene) of Ecoparc de Can Mata (ECM; els Hostalets de Pierola, Vallès-Penedès Basin, NE Iberian Peninsula). These specimens, referable to the extinct genus <i>Cheirogaster</i>, differ significantly from <i>C. bolivari</i> and are assigned to <i>C. richardi</i>, whose cranial morphology was previously unknown. This nominal taxon had been considered a junior subjective synonym of <i>C. bolivari</i>, due to a previous neotype designation for the former, based on shell remains, that did not meet the requirements of the <i>International Code of Zoological Nomenclature</i>. This designation is here considered invalid because it was based on material from a different geographical area, even though remains from the original type locality area were available. Given that the holotype of <i>C. richardi</i> (from the early Vallesian of els Hostalets de Pierola) has been destroyed, to clarify the taxonomic status of this taxon we here designate one of the two ECM skulls as the neotype of the species. On this basis, an emended diagnosis is provided, which leads us to conclude that two different species are recorded from the Iberian Miocene: <i>C. bolivari</i>, from the middle Aragonian of the inner Iberian basins; and <i>C. richardi</i>, from the latest Aragonian and Vallesian of the Vallès-Penedès Basin. Additional cranial material of <i>Cheirogaster</i> from inner Iberia would be required to clarify whether these species display distinct geographical distributions and/or different chronostratigraphical ranges. A cladistic analysis of Testudinidae based on cranial morphology supports a sister-taxon relationship between <i>Cheirogaster</i> and <i>Centrochelys</i>. Overall, our results highlight the significance of cranial morphology for attaining a better understanding of turtle taxonomy and phylogenetic relationships.