GTOBAS: fitting continuum functions with Gaussian-type orbitals

Fauré, Alexandre; Gorfinkiel, Jimena D.; Morgan, L A; Tennyson, Jonathan

doi:10.1016/s0010-4655(02)00141-8

Cited by 245 publications

(175 citation statements)

References 13 publications

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“…The complete molecular orbital representation in terms of occupied and virtual target molecular orbitals is constructed using the Hartree-Fock self-consistent field method with Gaussian-type orbitals (GTOs) and the continuum orbitals of Faure et al [26] and include up to g (l = 4) orbitals. The benefit of employing a partial-wave expansion for a low-energy electron molecule interaction is its rapid convergence.…”

Section: A Target Model Used For Low-energy Calculationsmentioning

confidence: 99%

Computation of electron-impact rotationally elastic total cross sections for methanol over an extensive range of impact energy (0.1 – 2000 eV)

Vinodkumar¹,

Limbachiya²,

Barot³

et al. 2013

Phys. Rev. A

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Theoretical rotationally elastic total cross sections for electron scattering from methanol over the incident energy range 0.1-2000 eV are presented. The computation of such cross sections for methanol is reported over such an extended energy range. We have employed two distinct formalisms to compute the cross sections across this energy range; between 0.1 eV and the ionization threshold of the target we have used the ab initio R-matrix method, while at higher energies the spherical complex optical potential method is invoked. The results from both formalisms match quite well at energies where they overlap and hence imply that they are consistent with each other. These total cross-section results are also in very good agreement with available experimental data and earlier theoretical data. The composite methodology employed here is well established and can be used to predict cross sections for other targets where data is scarce or not available.

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Section: A Target Model Used For Low-energy Calculationsmentioning

confidence: 99%

Computation of electron-impact rotationally elastic total cross sections for methanol over an extensive range of impact energy (0.1 – 2000 eV)

Vinodkumar¹,

Limbachiya²,

Barot³

et al. 2013

Phys. Rev. A

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“…In order to check that the assumption of zero amplitude of target electrons density on the R-matrix sphere is satisfied, we performed tests with R-matrix radii (and the corresponding basis sets) of 13a 0 , 15a 0 and 18a 0 . (The basis set for radius a = 13a 0 was optimized by Faure et al, 44 the one for a = 15a 0 was optimized by Bouchiha et al 45 and the basis set for radius a = 18a 0 is due to Tarana. 46 ) We can now turn to the description of our scattering models and results.…”

Section: Scattering Calculationsmentioning

confidence: 99%

Elastic and inelastic low-energy electron collisions with pyrazine

Mašín

Gorfinkiel

2011

The Journal of Chemical Physics

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We present results of ab-initio scattering calculations for electron collisions with pyrazine using the R-matrix method, carried out at various levels of approximation. We confirm the existing experimental and theoretical understanding of the three well-known π * shape resonances. In addition, we find numerous core-excited resonances (above 4.8 eV) and identify their most likely parent states. We also present differential cross sections, showing high sensitivity to the scattering model chosen at low energies. We make recommendations regarding the selection of models for scattering calculations with this type of targets.

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“…(20) remains valid even when considered between box eigenstates, the transition matrix elements themselves do differ from those evaluated between scattering states. In Appendix A we derive and discuss at length the above equations.…”

Section: Dipole Transition Matrix Elementsmentioning

confidence: 99%

“…Consequently, continuum orbitals obtained numerically from Gaussian functions can only be reliable either in a limited radial domain or within few eV from threshold opening [13][14][15]. Nevertheless, Gaussian functions have been rather successful in describing one-photon ionization of molecules to first order of perturbation theory [16][17][18][19][20][21], since the very localized nature of the ground state effectively restricts the spatial region in which ionization is produced. A similar restriction does not apply to above-threshold ionization (ATI) or to ionization beyond the perturbative regime, thus making the use of Gaussian functions unsuitable for the description * luca.argenti@uam.es of many ultrafast phenomena in the electronic continuum of molecules.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Gaussian–B-spline basis for the electronic continuum: Photoionization of atomic hydrogen

2014

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As a first step towards meeting the recent demand for new computational tools capable of reproducing molecular-ionization continua in a wide energy range, we introduce a hybrid Gaussian-B-spline basis (GABS) that combines short-range Gaussian functions, compatible with standard quantum-chemistry computational codes, with B splines, a basis appropriate to represent electronic continua. We illustrate the performance of the GABS hybrid basis for the hydrogen atom by solving both the time-independent and the time-dependent Schrödinger equation for a few representative cases. The results are in excellent agreement with those obtained with a purely B-spline basis, with analytical results, when available, and with recent above-threshold ionization spectra from the literature. In the latter case, we report fully differential photoelectron distributions which offer further insight into the process of above-threshold ionization at different wavelengths.

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GTOBAS: fitting continuum functions with Gaussian-type orbitals

Cited by 245 publications

References 13 publications

Computation of electron-impact rotationally elastic total cross sections for methanol over an extensive range of impact energy (0.1 – 2000 eV)

Computation of electron-impact rotationally elastic total cross sections for methanol over an extensive range of impact energy (0.1 – 2000 eV)

Elastic and inelastic low-energy electron collisions with pyrazine

Hybrid Gaussian–B-spline basis for the electronic continuum: Photoionization of atomic hydrogen

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