# Semiclassical approximations to real-time quantum-mechanical effects in correlation functions of complex molecular systems

## Abstract

Semiclassical approximation of real-time quantum effects is analyzed with the aid of the semiclassical initial value representation (SC-IVR) and Wigner distribution functions. We utilize these two ingredients to propose a new version of the semiclassical correlation function that contains, in principle, all quantum-mechanical effects. The advantage of this formulation is that it allows for a stepwise approximation specifically for real-time quantum effects based on a gradual inclusion of more degrees of freedom into the integral responsible for interference. From numerical calculations, this procedure does not seem to depend significantly on the choice coordinates if all degrees of freedom are coupled. This freedom from the coordinate choice removes possible ambiguities in applying this method. Several example cases are presented to demonstrate the usefulness of this approach. (c) 2000 American Institute of Physics.

- Authors:

- Department of Chemistry, University of California, Berkeley, California 94720 (United States)

- Publication Date:

- OSTI Identifier:
- 20216293

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Chemical Physics

- Additional Journal Information:
- Journal Volume: 112; Journal Issue: 19; Other Information: PBD: 15 May 2000; Journal ID: ISSN 0021-9606

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 74 ATOMIC AND MOLECULAR PHYSICS; CORRELATION FUNCTIONS; SEMICLASSICAL APPROXIMATION; QUANTUM MECHANICS; MOLECULES; ELECTRONIC STRUCTURE; HARMONIC OSCILLATORS; WIGNER DISTRIBUTION; MORSE POTENTIAL; THEORETICAL DATA

### Citation Formats

```
Sun, Sean X.
```*Semiclassical approximations to real-time quantum-mechanical effects in correlation functions of complex molecular systems*. United States: N. p., 2000.
Web. doi:10.1063/1.481429.

```
Sun, Sean X.
```*Semiclassical approximations to real-time quantum-mechanical effects in correlation functions of complex molecular systems*. United States. doi:10.1063/1.481429.

```
Sun, Sean X. Mon .
"Semiclassical approximations to real-time quantum-mechanical effects in correlation functions of complex molecular systems". United States. doi:10.1063/1.481429.
```

```
@article{osti_20216293,
```

title = {Semiclassical approximations to real-time quantum-mechanical effects in correlation functions of complex molecular systems},

author = {Sun, Sean X.},

abstractNote = {Semiclassical approximation of real-time quantum effects is analyzed with the aid of the semiclassical initial value representation (SC-IVR) and Wigner distribution functions. We utilize these two ingredients to propose a new version of the semiclassical correlation function that contains, in principle, all quantum-mechanical effects. The advantage of this formulation is that it allows for a stepwise approximation specifically for real-time quantum effects based on a gradual inclusion of more degrees of freedom into the integral responsible for interference. From numerical calculations, this procedure does not seem to depend significantly on the choice coordinates if all degrees of freedom are coupled. This freedom from the coordinate choice removes possible ambiguities in applying this method. Several example cases are presented to demonstrate the usefulness of this approach. (c) 2000 American Institute of Physics.},

doi = {10.1063/1.481429},

journal = {Journal of Chemical Physics},

issn = {0021-9606},

number = 19,

volume = 112,

place = {United States},

year = {2000},

month = {5}

}