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We calculate electron impact partial and total ionization cross sections of R-carvone (C10H14O), 2-butanol (C4H10O), imidazole (C3H4N2), and 2-nitroimidazole (C3H3N3O2). We have used the Binary Encounter Bethe (BEB) model to obtain total electron impact ionization cross sections (TICSs). The modified BEB method in combination with mass spectrum data of the molecules is used to calculate the partial ionization cross section (PICS) of the cationic fragments dissociating from the parent molecule. Our PICS data for R-carvone and 2-butanol are in good agreement with the experimental data for all the cation fragments along with the TICS data. For imidazole and 2-nitroimidazole, the estimates of the PICS are reported for the first time in the present study. We have found that both the modified BEB method and the mass spectrum dependence method work effectively to estimate PICS if we have information about the appearance energies and relative abundance data of the target under investigation. [ABSTRACT FROM AUTHOR]

We have calculated the electron and positron impact ionization of a set of molecules, S F 6 − n H n (n = 0 − 6) , S C l n (n = 1 − 6) , S F n − 1 C l (n = 1 − 6) and S F 5 X (X = C N , C F O) , for which there are much fewer data in the literature. We have optimized the targets, and their electric polarizability is calculated along with their orbital binding and kinetic energies within the Hartree–Fock approximation that serve as input to the Binary Encounter Bethe (BEB) model for both electron and positron ionization. Most of the targets are investigated for the first time, apart from S F 6 , for which we compared our data with various experimental and theoretical data, giving us a good comparison. [ABSTRACT FROM AUTHOR]

Two independent methods, namely, Binary-encounter Bethe (BEB) and complex scattering potential-ionization contribution (CSP-ic) methods, are employed to calculate the total ionization cross section (Qion) for cyclic organic molecules from ionization threshold to 5 keV for which there is a paucity of data in the literature. The Qion calculated with the (BEB/ωB97X) combination is found to give good agreement with the experimental results, the CSP-ic method, and the Qion calculated from Irikura orbital energies. The Qion for most of the targets are calculated for the first time over such a wide energy range. Hence, to check the consistency and reliability of the present data, we have also computed the static polarizability for all the targets and the variation of maximum ionization cross section (Qion,max) with polarizability is studied. A linear relationship is observed between these quantities indicating the consistency and reliability of the present Qion data. The targets studied are important for industrial applications, radiation biology, and astrophysics. [ABSTRACT FROM AUTHOR]

The theoretical calculations of electron impact total ionization cross section for cycloalkane, aldehyde, and ketone group molecules are undertaken from ionization threshold to 2 keV. The present calculations are based on the spherical complex optical potential formalism and complex scattering potential ionization contribution method. The results of most of the targets studied compare fairly well with the recent measurements, wherever available and the cross sections for many targets are predicted for the first time. The correlation between the peak of ionization cross sections with number of target electrons and target parameters is also reported. It was found that the cross sections at their maximum depend linearly with the number of target electrons and with other target parameters, confirming the consistency of the values reported here. [ABSTRACT FROM AUTHOR]

The present article reports calculated elastic, differential, momentum transfer and excitation cross section for electron scattering from BF and BF2 radicals using the ab initio R-matrix method. The calculations are performed with complete active space—configuration interaction and static exchange models for both targets to yield scattering cross sections and resonance parameters. Elastic and momentum transfer cross sections are also calculated using the spherical complex optical potential method to cover a wide energy range. The total ionization cross section is also reported from ionization threshold to 5 keV. The calculated cross sections for these neutral species are important for BF3 plasma and are reported for the first time to the best of our knowledge except ionization. [ABSTRACT FROM AUTHOR]

The present article reports calculated elastic, differential, momentum transfer and excitation cross section for electron scattering from BF and BF2 radicals using the ab initio R-matrix method. The calculations are performed with complete active space—configuration interaction and static exchange models for both targets to yield scattering cross sections and resonance parameters. Elastic and momentum transfer cross sections are also calculated using the spherical complex optical potential method to cover a wide energy range. The total ionization cross section is also reported from ionization threshold to 5 keV. The calculated cross sections for these neutral species are important for BF3 plasma and are reported for the first time to the best of our knowledge except ionization. [ABSTRACT FROM AUTHOR]

The ab initio R-matrix method is employed to study the electronic excitation of low-lying target states, the dissociation cross sections, and the rotational cross sections of the NH radical by electron impact for energies up to 15 eV. We have included dynamic interaction in our scattering model that uses close coupling formalism. There are 24 target states whose vertical excitation energies are below 15 eV, which are included in the trial wavefunction of the entire scattering system. In our scattering model, two electrons are frozen in the 1σ2 configuration and the remaining six electrons are free to move in the molecular orbitals 2σ 3σ 4σ 5σ 6σ 1π and 2π. The cc-pVTZ Dunning basis sets are used to optimize the target structure and electron scattering. The vibrationally resolved cross sections for transition from the ground state X 3Σ− to excited state c 1Π are computed by scaling the corresponding electronic excitation cross section by Franck-Condon factors. These factors are evaluated by using accurate potential energy curves of the ground state and the c excited state. We have compared the excitation cross section for the optically allowed transition X 3Σ− to A 3Π computed using our scattering model with the corresponding cross section evaluated in Born approximation, and the agreement is quite good indicating that for a reasonably high transition moment and a low threshold of the excited state, the effects of correlation and polarization are not very significant. The dissociative excitation cross section by electron impact into atomic fragments N and H is also shown which are caused mainly by c 1Π and a purely repulsive state 1 5Σ−. We have also shown that the vibrational cross section evaluated in Born approximation for the fundamental transition 0–1 of the ground state is quite small as compared to the rotational cross sections. The rotational cross sections are computed for j = 0 to j′ = 0–5, and it is shown that the dipole induced transition is predominant with an order of magnitude higher than the pure rotational 0–0 cross section. We have detected many low-lying core-excited shape resonances and provided their resonance parameters which form an important input to estimate dissociative electron attachment cross sections. [ABSTRACT FROM AUTHOR]

The total ionization cross section for CF ( x = 1 − 6) and CF ( x = 1 − 8) fluorocarbon species are studied with the Binary-Encounter Bethe (BEB) model using various orbital parameters calculated from restricted/unrestricted Hartree-Fock (RHF/UHF) and Density Functional Theory (DFT). All the targets were optimized for their minimal structures and energies with several ab-initio methods with the aug-cc-pVTZ basis set. Among them, the present results with RHF/UHF orbital energies showed good agreement with the experimental results for stable targets CF, CF, CF and CF. The results with the DFT ( ωB97X/ ωB97X-D) showed a reasonable agreement with the recent calculation of Bull et al. [J.N. Bull, M. Bart, C. Vallance, P.W. Harland, Phys. Rev. A 88, 062710 (2013)] for CF, CF and CF targets. The ionization cross section for CF, CF, CF, CF, CF, CF, CF, CF and CF were computed for the first time in the present study. We have also computed the vertical ionization potentials and polarizability for all the targets and compared them with other experimental and theoretical values. A good agreement is found between the present and the previous results. The calculated polarizability in turn is used to study the correlation with maximum ionization cross section and in general a good correlation is found among them, confirming the consistency and reliability of the present data. The cross section data reported in this article are very important for plasma modeling especially related to fluorocarbon plasmas. Graphical abstract: [ABSTRACT FROM AUTHOR]

In this article, we report the electron impact ionization cross sections for atoms Si, P, S, Sc, Cr, Mn, Co, Zn, Ga, Ge, Nb, Rh, and Cd, having applications in different areas of applied science and technology. The energy regime for the calculation is from the ionization threshold of the target to 2000 eV. We have employed the spherical complex optical potential method to calculate inelastic cross sections. A semiempirical complex scattering potential ionization contribution method is then used to estimate the ionization cross section from the inelastic cross section. In general, good agreement between the present results with available theoretical datasets and measurements are observed. The prime focus of this study was to investigate electron impact ionization phenomena in less studied targets. The results obtained are found to be quite encouraging. The values presented here are reasonable estimates of cross section for all the atoms studied. [ABSTRACT FROM AUTHOR]

We report here the total ionisation cross section for chlorofluoromethanes, namely CCl3F (Freon 11), CCl2F2(Freon 12), CClF3(Freon 13), CHCl2F (Freon 21), CHClF2(Freon 22), CH2ClF (Freon 31), CCl4and CClx(x= 1–3), radicals by electron impact from ionisation threshold to 2 keV. The total inelastic cross section is obtained employing a complex optical potential formalism and solving the Schrödinger equation through partial wave analysis. Using the complex scattering potential-ionisation contribution method, the total ionisation cross section is derived from the inelastic cross section for these targets. The results obtained are then compared with the existing experimental and theoretical data, wherever available. The present result shows reasonable agreement with previous data. For the CClxradicals, the ionisation cross section is predicted for the first time. The data reported here have immense interest to atmospheric and technological plasma modelling. [ABSTRACT FROM AUTHOR]

In this article, we have reported electron impact total ionisation cross sections for the bio-molecules pyridine, pyrimidine, n-propylamine, urea, formamide and N-methylformamide from ionisation threshold to 2000 eV. The present calculations are based on the spherical complex optical potential formalism and complex scattering potential ionisation contribution method. The results obtained for pyridine and pyrimidine are compared with available theoretical and experimental results and are found to be in excellent agreement with existing data. The ionisation cross sections for other molecules are reported for the first time. An interesting relation between the peak of inelastic and ionisation cross sections with target parameters is also reported. It was found that both the cross sections at their maximum depend linearly with these parameters, confirming the consistency of the values reported here. [ABSTRACT FROM PUBLISHER]

Highlights: [•] Quantum mechanical approximation to find inelastic cross section from ∼10 to 5000eV. [•] Semi-empirical formalism to extract ionization fraction from inelastic cross section. [•] SCOP and CSP-ic methods found to give very good comparison with existing data. [•] Group additivity rule is incorporated for large targets. [•] Cross section for CBr4 is reported for the first time. [Copyright &y& Elsevier]

Highlights: [•] Quantum mechanical models were used to find TCS for e-Cl2O from 0.1 to 2000eV. [•] R-matrix method at low energies (<13eV) and SCOP at high energies (13–2000eV). [•] Besides TCS, DCS, excitation cross section and momentum transfer CS also predicted. [•] R-matrix method identifies resonances with a possibility of DEA formation. [•] Resonance detected at 1.88eV is associated with Cl2O− anion formation. [Copyright &y& Elsevier]

Calculation of electron impact total and ionization cross sections for Sr, Y, Ru, Pd, and Ag atoms were performed using spherical complex optical potential and complex scattering potential-ionization contribution methods. The complex optical potential model is formulated from the target parameters and the atomic charge density. The spherical charge densities are in turn derived from the Roothaan-Hartree-Fock wavefunctions defining the atomic orbital of the target. In the present study cross sections are computed in the energy range from ionization threshold to 2000 eV. The results obtained are compared with other theories and measurements wherever available and were found to be quite consistent and uniform. In general, present data show an overall reasonable agreement with other results. Dependence of total cross sections on the number of target electrons and peak of ionization cross section on target parameters were also found to be consistent with previous observations. [ABSTRACT FROM AUTHOR]

Abstract: We report here the total cross section for chloroflouromethanes namely CCl3F (Freon 11), CCl2F2 (Freon 12), CClF3 (Freon 13), CCl4 and CClx (x =1–3), radicals by electron impact 50 to 5000eV. The total inelastic and elastic cross sections are obtained employing a complex optical potential formalism and solving the Schrödinger equation through partial wave analysis. The total cross section is obtained as the sum of total inelastic and elastic cross sections. The results obtained are compared with the existing experimental and theoretical data, wherever available. The present result shows reasonable agreement with previous data. For the CClx radicals, we have predicted the total cross sections for the first time. The data reported here has immense interest to atmospheric and technological plasma modelling. [Copyright &y& Elsevier]