Back to Search
Start Over
A Multichannel Least-Squares B-Spline Approach to Molecular Photoionization: Theory, Implementation, and Applications within the Configuration-Interaction Singles Approximation
- Publication Year :
- 2016
-
Abstract
- We describe, in detail, a basis set approach to the multichannel scattering problem. The full set of linearly independent scattering states at each prefixed energy of the continuum spectrum can be obtained via a least-squares approach. To test the algorithm in a concrete setup, we report a parallel implementation of the close-coupling method in which the final states are treated within the configuration interaction singles (CIS) approximation. The method requires, as input, a set of orthonormal orbitals, obtained from any quantum chemistry package. A one-center expansion (OCE) basis set consisting of products of radial B-splines and symmetry adapted angular functions is then used to expand the continuum electron wave function. To assess the quality of the CIS approximation, we compute total and partial cross sections and angular asymmetry parameters for the photoionization of a selection of closed-shell atoms (He, Ne, and Ar), H-2, H2O, and ethylene. Results are compared with the experimental data and with theoretical predictions obtained with time-dependent density functional theory (TDDFT). It is seen that, generally, the photoionization observables obtained at the CIS level compare well with TDDFT predictions. The same basis can be employed to describe molecular multiphoton or strong field ionization.
- Subjects :
- Physics
Mathematical optimization
010304 chemical physics
Basis (linear algebra)
Computer Science Applications1707 Computer Vision and Pattern Recognition
Physical and Theoretical Chemistry
Time-dependent density functional theory
Photoionization
Configuration interaction
01 natural sciences
Computer Science Applications
Computational physics
0103 physical sciences
Orthonormal basis
Density functional theory
010306 general physics
Wave function
Basis set
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....62589a7e58098d00a3c9f4bea299f865