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DOI: 10.6084/m9.figshare.1012622.v1
title: The resonant energy <em>E<sub>di</sub></em> (eV), radiative transition probabilities <em>A<sub>di</sub></em> (<em>s</em><sup>−1</sup>) and total natural width Γ<sub><em>d</em></sub> (eV) of the 2s<em>n</em>p <sup>1, 3</sup>P<sub>1</sub> resonant transitions to the ground states of Fe<sup>16+</sup>, Kr<sup>26+</sup> and Xe<sup>44+</sup>

description: <b>Table 4.</b> The resonant energy <em>E<sub>di</sub></em> (eV), radiative transition probabilities <em>A<sub>di</sub></em> (<em>s</em><sup>−1</sup>) and total natural width Γ<sub><em>d</em></sub> (eV) of the 2s<em>n</em>p <sup>1, 3</sup>P<sub>1</sub> resonant transitions to the ground states of Fe<sup>16+</sup>, Kr<sup>26+</sup> and Xe<sup>44+</sup>. B and C represent the Babushkin gauge and Coulomb gauge, respectively. <em>a</em>(<em>b</em>) represents <em>a</em> <b>×</b> 10<sup><em>b</em></sup>. <strong>Abstract</strong> Photoionization (PI) cross sections of the ground state 1s<sup>2</sup> 2s<sup>2</sup> 2p<sup>6</sup><sup>1</sup> S<sub>0</sub> of Ne-like Ar<sup>8+</sup>, Fe<sup>16+</sup>, Kr<sup>26+</sup> and Xe<sup>44+</sup> ions are calculated by using the Dirac atomic <em>R</em>-matrix code based on a fully relativistic <em>R</em>-matrix method. To analyze the detailed resonant structure, systematical calculations based on the multiconfiguration Dirac–Fock method are performed for the dominant 2s → <em>n</em>p resonant transitions, and the resonant energies, strengths and total natural widths are presented. The resonant structures and characteristics of the PI cross sections and resonance strengths along the Ne-like sequence are discussed with emphasis on the influence of relativistic effects. For the Ar<sup>8+</sup> ion, good agreement is found between the present results and available theoretical calculations and experimental data.
DOI: 10.6084/m9.figshare.1012619.v1
title: Fine structure energies (in eV) of Ar<sup>9+</sup>, Fe<sup>17+</sup>, Kr<sup>27+</sup> and Xe<sup>45+</sup> target ions

description: <b>Table 1.</b> Fine structure energies (in eV) of Ar<sup>9+</sup>, Fe<sup>17+</sup>, Kr<sup>27+</sup> and Xe<sup>45+</sup> target ions. <strong>Abstract</strong> Photoionization (PI) cross sections of the ground state 1s<sup>2</sup> 2s<sup>2</sup> 2p<sup>6</sup><sup>1</sup> S<sub>0</sub> of Ne-like Ar<sup>8+</sup>, Fe<sup>16+</sup>, Kr<sup>26+</sup> and Xe<sup>44+</sup> ions are calculated by using the Dirac atomic <em>R</em>-matrix code based on a fully relativistic <em>R</em>-matrix method. To analyze the detailed resonant structure, systematical calculations based on the multiconfiguration Dirac–Fock method are performed for the dominant 2s → <em>n</em>p resonant transitions, and the resonant energies, strengths and total natural widths are presented. The resonant structures and characteristics of the PI cross sections and resonance strengths along the Ne-like sequence are discussed with emphasis on the influence of relativistic effects. For the Ar<sup>8+</sup> ion, good agreement is found between the present results and available theoretical calculations and experimental data.
DOI: 10.6084/m9.figshare.1012586
title: Parameters of the diabatic term

description: <b>Table 2.</b> Parameters of the diabatic term. <strong>Abstract</strong> Energy spectra of electrons ejected into <sup>3</sup>He<sup>2+</sup>–H<sub>2</sub> collisions have been measured in the incident ion energy range 6–30 keV. Parameters of the quasimolecule formed during the collision are determined. The dominant role of the channel (2a')<sup>2</sup> → 1a'3a' → 1a' + <em>e</em> in the production of electrons at keV ion energies has been revealed. The structure associated with autoionization transitions in the projectile helium atoms shows enormously large broadening and shift to lower energies.
DOI: 10.6084/m9.figshare.1012585
title: The function <em>F</em>(<em>R</em>)

description: <b>Table 1.</b> The function <em>F</em>(<em>R</em>). <strong>Abstract</strong> Energy spectra of electrons ejected into <sup>3</sup>He<sup>2+</sup>–H<sub>2</sub> collisions have been measured in the incident ion energy range 6–30 keV. Parameters of the quasimolecule formed during the collision are determined. The dominant role of the channel (2a')<sup>2</sup> → 1a'3a' → 1a' + <em>e</em> in the production of electrons at keV ion energies has been revealed. The structure associated with autoionization transitions in the projectile helium atoms shows enormously large broadening and shift to lower energies.
DOI: 10.6084/m9.figshare.1012585.v1
title: The function <em>F</em>(<em>R</em>)

description: <b>Table 1.</b> The function <em>F</em>(<em>R</em>). <strong>Abstract</strong> Energy spectra of electrons ejected into <sup>3</sup>He<sup>2+</sup>–H<sub>2</sub> collisions have been measured in the incident ion energy range 6–30 keV. Parameters of the quasimolecule formed during the collision are determined. The dominant role of the channel (2a')<sup>2</sup> → 1a'3a' → 1a' + <em>e</em> in the production of electrons at keV ion energies has been revealed. The structure associated with autoionization transitions in the projectile helium atoms shows enormously large broadening and shift to lower energies.
DOI: 10.6084/m9.figshare.1012578
title: Present experimental total cross sections (TCSs) for positron scattering from iodomethane

description: <b>Table 1.</b> Present experimental total cross sections (TCSs) for positron scattering from iodomethane. The errors represent the statistical component (±1σ) of the overall uncertainties only. <strong>Abstract</strong> We report experimental total cross sections (TCSs) and calculated elastic integral cross sections (ICSs) for positron collisions with iodomethane (methyl iodide, CH<sub>3</sub>I). The experimental TCSs were obtained with a linear transmission technique, for energies from 0.1 up to 50 eV. The present TCS data agree well with those previously reported (Kimura <em>et al</em> 2001 <em>J. Chem. Phys.</em> <strong>115</strong> 7442) at higher energies (above 7 eV), but significant discrepancies are found at the lower energies. The present ICS computations were performed with the Schwinger multichannel method (SMC) and the Born dipole approximation in the incident energy range from 0.1 eV up to 10 eV. Iodomethane poses a great challenge to theoretical descriptions of the collisions dynamics. In addition to the neglect of inelastic channels, the main difficulty found in the SMC approach is related to numerical limitations that prevent a thorough description of correlation–polarization effects. Although our ICS calculations do not compare well with the present TCS data, the results are encouraging, as iodomethane would challenge all the presently available computational approaches.
DOI: 10.6084/m9.figshare.1012578.v1
title: Present experimental total cross sections (TCSs) for positron scattering from iodomethane

description: <b>Table 1.</b> Present experimental total cross sections (TCSs) for positron scattering from iodomethane. The errors represent the statistical component (±1σ) of the overall uncertainties only. <strong>Abstract</strong> We report experimental total cross sections (TCSs) and calculated elastic integral cross sections (ICSs) for positron collisions with iodomethane (methyl iodide, CH<sub>3</sub>I). The experimental TCSs were obtained with a linear transmission technique, for energies from 0.1 up to 50 eV. The present TCS data agree well with those previously reported (Kimura <em>et al</em> 2001 <em>J. Chem. Phys.</em> <strong>115</strong> 7442) at higher energies (above 7 eV), but significant discrepancies are found at the lower energies. The present ICS computations were performed with the Schwinger multichannel method (SMC) and the Born dipole approximation in the incident energy range from 0.1 eV up to 10 eV. Iodomethane poses a great challenge to theoretical descriptions of the collisions dynamics. In addition to the neglect of inelastic channels, the main difficulty found in the SMC approach is related to numerical limitations that prevent a thorough description of correlation–polarization effects. Although our ICS calculations do not compare well with the present TCS data, the results are encouraging, as iodomethane would challenge all the presently available computational approaches.
DOI: 10.6084/m9.figshare.1012573
title: Fitting parameters <em>a<sub>i</sub></em> of the fifth-order polynomial alpha (T_{e}) = sum ^5_{i=0} a_i T_e^i and scaling parameters <em>E</em><sub>0</sub> to reproduce the scaled PRC for Sn<sup>4 +</sup> through Sn<sup>13 +</sup> ions

description: <b>Table 3.</b> Fitting parameters <em>a<sub>i</sub></em> of the fifth-order polynomial \alpha (T_{e}) = \sum ^5_{i=0} a_i T_e^i and scaling parameters <em>E</em><sub>0</sub> to reproduce the scaled PRC for Sn<sup>4 +</sup> through Sn<sup>13 +</sup> ions. The numbers in square brackets are powers of 10 to be multiplied with the preceding numbers, respectively. <strong>Abstract</strong> Electron-impact single-ionization cross sections of Sn<sup><em>q</em> +</sup> ions in charge states <em>q</em> = 4–13 with 4d<sup>[10 − (<em>q</em> − 4)]</sup> outer-shell configurations have been studied in the energy range from the corresponding thresholds up to 1000 eV. Absolute cross sections and fine-step energy-scan data have been measured employing the crossed-beams technique. Contributions of different ionization mechanisms have been analysed by comparing the experimental data with calculations employing the configuration-averaged distorted wave approximation. Ionization plasma rate coefficients inferred from the experimental data are also presented.
DOI: 10.6084/m9.figshare.1012572
title: Overview of the inner-subshell excitations <em>n</em><sub>0</sub><em>l</em><sub>0</sub> → <em>nl</em> included in the present calculations

description: <b>Table 2.</b> Overview of the inner-subshell excitations <em>n</em><sub>0</sub><em>l</em><sub>0</sub> → <em>nl</em> included in the present calculations. All subshells with quantum numbers <em>nl</em>, where <em>n</em> ≤ <em>n</em><sub>max</sub> and <em>l</em> ≤ <em>l</em><sub>max</sub>, providing at least one vacancy to which the <em>n</em><sub>0</sub><em>l</em><sub>0</sub> electron can be excited were considered. The orbital quantum numbers <em>l</em><sub>0</sub>, <em>l</em><sub>max</sub> = 0, 1, 2, ... are expressed by their spectroscopic symbols s, p, d,..., respectively. For ions in the ground-state configuration, <em>m</em> is the number of electrons in the 4d subshell. It is equal to 10 for Sn<sup>4 +</sup> and 1 for Sn<sup>13 +</sup>. As far as long-lived excited ions are concerned, we only had to consider 4d-subshell-excited configurations for the charge states up to <em>q</em> = 12. In the configurations of interest, the 4d subshell is initially populated with <em>m</em> − 1 electrons and the excited electron is initially in subshell <em>n</em><sub>1</sub><em>l</em><sub>1</sub>. The subshells <em>n</em><sub>1</sub><em>l</em><sub>1</sub> taken into account in the present analysis are listed in table 1. For the case of Sn<sup>13 +</sup>, the only excited configuration of relevance to the present measurements is the 4p<sup>5</sup>4d<sup>2</sup> configuration. <strong>Abstract</strong> Electron-impact single-ionization cross sections of Sn<sup><em>q</em> +</sup> ions in charge states <em>q</em> = 4–13 with 4d<sup>[10 − (<em>q</em> − 4)]</sup> outer-shell configurations have been studied in the energy range from the corresponding thresholds up to 1000 eV. Absolute cross sections and fine-step energy-scan data have been measured employing the crossed-beams technique. Contributions of different ionization mechanisms have been analysed by comparing the experimental data with calculations employing the configuration-averaged distorted wave approximation. Ionization plasma rate coefficients inferred from the experimental data are also presented.
DOI: 10.6084/m9.figshare.1012573.v1
title: Fitting parameters <em>a<sub>i</sub></em> of the fifth-order polynomial alpha (T_{e}) = sum ^5_{i=0} a_i T_e^i and scaling parameters <em>E</em><sub>0</sub> to reproduce the scaled PRC for Sn<sup>4 +</sup> through Sn<sup>13 +</sup> ions

description: <b>Table 3.</b> Fitting parameters <em>a<sub>i</sub></em> of the fifth-order polynomial \alpha (T_{e}) = \sum ^5_{i=0} a_i T_e^i and scaling parameters <em>E</em><sub>0</sub> to reproduce the scaled PRC for Sn<sup>4 +</sup> through Sn<sup>13 +</sup> ions. The numbers in square brackets are powers of 10 to be multiplied with the preceding numbers, respectively. <strong>Abstract</strong> Electron-impact single-ionization cross sections of Sn<sup><em>q</em> +</sup> ions in charge states <em>q</em> = 4–13 with 4d<sup>[10 − (<em>q</em> − 4)]</sup> outer-shell configurations have been studied in the energy range from the corresponding thresholds up to 1000 eV. Absolute cross sections and fine-step energy-scan data have been measured employing the crossed-beams technique. Contributions of different ionization mechanisms have been analysed by comparing the experimental data with calculations employing the configuration-averaged distorted wave approximation. Ionization plasma rate coefficients inferred from the experimental data are also presented.
DOI: 10.6084/m9.figshare.1012571
title: Results of the analysis of excited primary-ion-beam admixtures possibly present in the experiment

description: <b>Table 1.</b> Results of the analysis of excited primary-ion-beam admixtures possibly present in the experiment. The calculations were performed using the Cowan code [27]. The estimated fractions are the coefficients <em>k<sup>E</sup></em> obtained from fitting equation (3) to the experimental data. Calculated excitation energies are given in column 4. The experimentally obtained ionization threshold energies (T.E.), T.E. taken from NIST Atomic Spectra Database [28] and T.E. calculated within the configuration-averaged approximation are provided in columns 5, 6 and 7, respectively. The estimated excited-levels' lifetimes and flight times of ions between the source and the interaction region are provided in the last two columns, respectively. The numbers in square brackets are powers of 10 to be multiplied with the preceding numbers, respectively. <strong>Abstract</strong> Electron-impact single-ionization cross sections of Sn<sup><em>q</em> +</sup> ions in charge states <em>q</em> = 4–13 with 4d<sup>[10 − (<em>q</em> − 4)]</sup> outer-shell configurations have been studied in the energy range from the corresponding thresholds up to 1000 eV. Absolute cross sections and fine-step energy-scan data have been measured employing the crossed-beams technique. Contributions of different ionization mechanisms have been analysed by comparing the experimental data with calculations employing the configuration-averaged distorted wave approximation. Ionization plasma rate coefficients inferred from the experimental data are also presented.
DOI: 10.6084/m9.figshare.1012572.v1
title: Overview of the inner-subshell excitations <em>n</em><sub>0</sub><em>l</em><sub>0</sub> → <em>nl</em> included in the present calculations

description: <b>Table 2.</b> Overview of the inner-subshell excitations <em>n</em><sub>0</sub><em>l</em><sub>0</sub> → <em>nl</em> included in the present calculations. All subshells with quantum numbers <em>nl</em>, where <em>n</em> ≤ <em>n</em><sub>max</sub> and <em>l</em> ≤ <em>l</em><sub>max</sub>, providing at least one vacancy to which the <em>n</em><sub>0</sub><em>l</em><sub>0</sub> electron can be excited were considered. The orbital quantum numbers <em>l</em><sub>0</sub>, <em>l</em><sub>max</sub> = 0, 1, 2, ... are expressed by their spectroscopic symbols s, p, d,..., respectively. For ions in the ground-state configuration, <em>m</em> is the number of electrons in the 4d subshell. It is equal to 10 for Sn<sup>4 +</sup> and 1 for Sn<sup>13 +</sup>. As far as long-lived excited ions are concerned, we only had to consider 4d-subshell-excited configurations for the charge states up to <em>q</em> = 12. In the configurations of interest, the 4d subshell is initially populated with <em>m</em> − 1 electrons and the excited electron is initially in subshell <em>n</em><sub>1</sub><em>l</em><sub>1</sub>. The subshells <em>n</em><sub>1</sub><em>l</em><sub>1</sub> taken into account in the present analysis are listed in table 1. For the case of Sn<sup>13 +</sup>, the only excited configuration of relevance to the present measurements is the 4p<sup>5</sup>4d<sup>2</sup> configuration. <strong>Abstract</strong> Electron-impact single-ionization cross sections of Sn<sup><em>q</em> +</sup> ions in charge states <em>q</em> = 4–13 with 4d<sup>[10 − (<em>q</em> − 4)]</sup> outer-shell configurations have been studied in the energy range from the corresponding thresholds up to 1000 eV. Absolute cross sections and fine-step energy-scan data have been measured employing the crossed-beams technique. Contributions of different ionization mechanisms have been analysed by comparing the experimental data with calculations employing the configuration-averaged distorted wave approximation. Ionization plasma rate coefficients inferred from the experimental data are also presented.
DOI: 10.6084/m9.figshare.1012571.v1
title: Results of the analysis of excited primary-ion-beam admixtures possibly present in the experiment

description: <b>Table 1.</b> Results of the analysis of excited primary-ion-beam admixtures possibly present in the experiment. The calculations were performed using the Cowan code [27]. The estimated fractions are the coefficients <em>k<sup>E</sup></em> obtained from fitting equation (3) to the experimental data. Calculated excitation energies are given in column 4. The experimentally obtained ionization threshold energies (T.E.), T.E. taken from NIST Atomic Spectra Database [28] and T.E. calculated within the configuration-averaged approximation are provided in columns 5, 6 and 7, respectively. The estimated excited-levels' lifetimes and flight times of ions between the source and the interaction region are provided in the last two columns, respectively. The numbers in square brackets are powers of 10 to be multiplied with the preceding numbers, respectively. <strong>Abstract</strong> Electron-impact single-ionization cross sections of Sn<sup><em>q</em> +</sup> ions in charge states <em>q</em> = 4–13 with 4d<sup>[10 − (<em>q</em> − 4)]</sup> outer-shell configurations have been studied in the energy range from the corresponding thresholds up to 1000 eV. Absolute cross sections and fine-step energy-scan data have been measured employing the crossed-beams technique. Contributions of different ionization mechanisms have been analysed by comparing the experimental data with calculations employing the configuration-averaged distorted wave approximation. Ionization plasma rate coefficients inferred from the experimental data are also presented.
DOI: 10.6084/m9.figshare.1012554
title: Energies and proposed assignments for structure due to valence or Rydberg states in the photoabsorption spectrum of pyridazine

description: <b>Table 5.</b> Energies and proposed assignments for structure due to valence or Rydberg states in the photoabsorption spectrum of pyridazine. <strong>Abstract</strong> The valence shell electronic states of pyridazine have been studied experimentally, by recording the photoabsorption spectrum, and theoretically, by calculating oscillator strengths and excitation energies. The absolute photoabsorption cross section has been measured between 4 and 40 eV, using synchrotron radiation, and is dominated by prominent bands associated with intravalence transitions. In contrast, structure due to Rydberg excitations is weak. One Rydberg state, belonging to a series converging onto the {\rm \tilde X}\;{}^2{\rm B}_{\rm 2} state limit has been observed and assigned. The accompanying vibrational structure has been characterized by analogy with that in the corresponding photoelectron band. Vibrational progressions associated with Rydberg states belonging to one or more series converging onto the {\rm \tilde A}\;{}^2{\rm A}_{\rm 2} state limit have also been observed. The absorption structure associated with these series is complex and only tentative assignments have been proposed for the Rydberg states. The time-dependent version of density functional theory has been used to calculate oscillator strengths and excitation energies for the optically allowed singlet–singlet valence transitions and also to obtain the excitation energies for electric-dipole-forbidden and/or spin-forbidden transitions. The valence shell photoionization dynamics have been investigated theoretically by calculating photoelectron angular distributions and photoionization partial cross sections of the four outermost orbitals. In addition, the ground state outer valence electronic configuration has been obtained at the complete active space self-consistent field and the N-electron valence state perturbation theory to second-order levels of theory.
DOI: 10.6084/m9.figshare.1012555
title: KS eigenvalue and virtual orbital character of the low-lying orbitals in pyridazine, obtained from a minimal basis set calculation

description: <b>Table 6.</b> KS eigenvalue and virtual orbital character of the low-lying orbitals in pyridazine, obtained from a minimal basis set calculation. <strong>Abstract</strong> The valence shell electronic states of pyridazine have been studied experimentally, by recording the photoabsorption spectrum, and theoretically, by calculating oscillator strengths and excitation energies. The absolute photoabsorption cross section has been measured between 4 and 40 eV, using synchrotron radiation, and is dominated by prominent bands associated with intravalence transitions. In contrast, structure due to Rydberg excitations is weak. One Rydberg state, belonging to a series converging onto the {\rm \tilde X}\;{}^2{\rm B}_{\rm 2} state limit has been observed and assigned. The accompanying vibrational structure has been characterized by analogy with that in the corresponding photoelectron band. Vibrational progressions associated with Rydberg states belonging to one or more series converging onto the {\rm \tilde A}\;{}^2{\rm A}_{\rm 2} state limit have also been observed. The absorption structure associated with these series is complex and only tentative assignments have been proposed for the Rydberg states. The time-dependent version of density functional theory has been used to calculate oscillator strengths and excitation energies for the optically allowed singlet–singlet valence transitions and also to obtain the excitation energies for electric-dipole-forbidden and/or spin-forbidden transitions. The valence shell photoionization dynamics have been investigated theoretically by calculating photoelectron angular distributions and photoionization partial cross sections of the four outermost orbitals. In addition, the ground state outer valence electronic configuration has been obtained at the complete active space self-consistent field and the N-electron valence state perturbation theory to second-order levels of theory.