# Correlated electron dynamics with time-dependent quantum Monte Carlo: Three-dimensional helium

## Abstract

Here the recently proposed time-dependent quantum Monte Carlo method is applied to three dimensional para- and ortho-helium atoms subjected to an external electromagnetic field with amplitude sufficient to cause significant ionization. By solving concurrently sets of up to 20 000 coupled 3D time-dependent Schroedinger equations for the guide waves and corresponding sets of first order equations of motion for the Monte Carlo walkers we obtain ground state energies in close agreement with the exact values. The combined use of spherical coordinates and B-splines along the radial coordinate proves to be especially accurate and efficient for such calculations. Our results for the dipole response and the ionization of an atom with un-correlated electrons are in good agreement with the predictions of the conventional time-dependent Hartree-Fock method while the calculations with correlated electrons show enhanced ionization that is due to the electron-electron repulsion.

- Authors:

- Physics Department, Sofia University, 1164 Sofia (Bulgaria)

- Publication Date:

- OSTI Identifier:
- 22038652

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Chemical Physics

- Additional Journal Information:
- Journal Volume: 135; Journal Issue: 4; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 74 ATOMIC AND MOLECULAR PHYSICS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ELECTROMAGNETIC FIELDS; ELECTRON CORRELATION; EQUATIONS OF MOTION; FORECASTING; GROUND STATES; HARTREE-FOCK METHOD; HELIUM; MONTE CARLO METHOD; SCHROEDINGER EQUATION; TIME DEPENDENCE

### Citation Formats

```
Christov, Ivan P.
```*Correlated electron dynamics with time-dependent quantum Monte Carlo: Three-dimensional helium*. United States: N. p., 2011.
Web. doi:10.1063/1.3615061.

```
Christov, Ivan P.
```*Correlated electron dynamics with time-dependent quantum Monte Carlo: Three-dimensional helium*. United States. doi:10.1063/1.3615061.

```
Christov, Ivan P. Thu .
"Correlated electron dynamics with time-dependent quantum Monte Carlo: Three-dimensional helium". United States. doi:10.1063/1.3615061.
```

```
@article{osti_22038652,
```

title = {Correlated electron dynamics with time-dependent quantum Monte Carlo: Three-dimensional helium},

author = {Christov, Ivan P.},

abstractNote = {Here the recently proposed time-dependent quantum Monte Carlo method is applied to three dimensional para- and ortho-helium atoms subjected to an external electromagnetic field with amplitude sufficient to cause significant ionization. By solving concurrently sets of up to 20 000 coupled 3D time-dependent Schroedinger equations for the guide waves and corresponding sets of first order equations of motion for the Monte Carlo walkers we obtain ground state energies in close agreement with the exact values. The combined use of spherical coordinates and B-splines along the radial coordinate proves to be especially accurate and efficient for such calculations. Our results for the dipole response and the ionization of an atom with un-correlated electrons are in good agreement with the predictions of the conventional time-dependent Hartree-Fock method while the calculations with correlated electrons show enhanced ionization that is due to the electron-electron repulsion.},

doi = {10.1063/1.3615061},

journal = {Journal of Chemical Physics},

issn = {0021-9606},

number = 4,

volume = 135,

place = {United States},

year = {2011},

month = {7}

}