A complex Gaussian approach to molecular photoionization

Abstract

We develop and implement a Gaussian approach to calculate partial cross-sections and asymmetry parameters for molecular photoionization. Optimal sets of complex Gaussian-type orbitals (cGTOs) are first obtained by non-linear optimization, to best fit sets of Coulomb or distorted continuum wave functions for relevant orbital quantum numbers. This allows us to represent the radial wavefunction for the outgoing electron with accurate cGTO expansions. Within a time-independent partial wave approach, we show that all the necessary transition integrals become analytical, in both length and velocity gauges, thus facilitating the numerical evaluation of photoionization observables. Illustrative results, presented for NH3 and H2O within a one-active-electron monocentric model, validate numerically the proposed strategy based on a complex Gaussian representation of continuum states.

32 pages, 1 table, 10 figures

References in corpus (3)

• Time-resolved photoelectron spectroscopy of non-adiabatic dynamics in polyatomic molecules
• Ab initio lifetime correction to scattering states for time-dependent electronic-structure calculations with incomplete basis sets
• Fitting continuum wavefunctions with complex Gaussians: Computation of ionization cross sections

Cited by in corpus (5)

• Calculation of electron-impact and photo-ionization cross sections of methane using analytical Gaussian integrals
• Multicenter integrals involving complex Gaussian type functions
• On the use of complex GTOs for the evaluation of radial integrals involving oscillating functions
• Free-particle Green's function matrix elements over spherical Gaussian and plane-wave-modulated Gaussian basis functions
• A complex Gaussian representation of continuum wavefunctions respectful of their asymptotic behaviour