# Accuracy of the centrifugal sudden approximation in the H + CHD{sub 3} → H{sub 2} + CD{sub 3} reaction

## Abstract

The initial state selected time-dependent wave packet method has been extended to calculate the coupled-channel reaction probabilities with total angular momentum J{sub tot} > 0 for the title reaction with seven degrees of freedom included. Fully converged integral cross sections were obtained for the ground and a number of vibrational excited initial states on a new potential energy surface recently constructed by this group using neural network fitting. As found from a previous study with the centrifugal sudden (CS) approximation, all these initial vibrational excitations investigated in this study enhance the reactivity considerably at a given collision energy, in particular the CH stretch excited state. The energy initially deposited in CH stretch motion is more effective than translational energy on promoting the reaction in the entire energy region, while for CH bending or CD{sub 3} umbrella excitations only at the high collision energy the vibrational energy becomes more effective. Our calculations also revealed that the accuracy of the CS approximation considerably deteriorates with the increase of J{sub tot}, in particular on the threshold energy. The CS approximation underestimates the integral cross sections for all these initial states, albeit not very severely. In general, it works better at high collision energiesmore »

- Authors:

- Publication Date:

- OSTI Identifier:
- 22420134

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Chemical Physics

- Additional Journal Information:
- Journal Volume: 140; Journal Issue: 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ACCURACY; ANGULAR MOMENTUM; COLLISIONS; DEGREES OF FREEDOM; DEPOSITS; EXCITATION; EXCITED STATES; INTEGRAL CROSS SECTIONS; NEURAL NETWORKS; POTENTIAL ENERGY; PROBABILITY; REACTIVITY; SUDDEN APPROXIMATION; THRESHOLD ENERGY

### Citation Formats

```
Zhang, Zhaojun, Chen, Jun, Liu, Shu, and Zhang, Dong H., E-mail: zhangdh@dicp.ac.cn.
```*Accuracy of the centrifugal sudden approximation in the H + CHD{sub 3} → H{sub 2} + CD{sub 3} reaction*. United States: N. p., 2014.
Web. doi:10.1063/1.4881517.

```
Zhang, Zhaojun, Chen, Jun, Liu, Shu, & Zhang, Dong H., E-mail: zhangdh@dicp.ac.cn.
```*Accuracy of the centrifugal sudden approximation in the H + CHD{sub 3} → H{sub 2} + CD{sub 3} reaction*. United States. doi:10.1063/1.4881517.

```
Zhang, Zhaojun, Chen, Jun, Liu, Shu, and Zhang, Dong H., E-mail: zhangdh@dicp.ac.cn. Sat .
"Accuracy of the centrifugal sudden approximation in the H + CHD{sub 3} → H{sub 2} + CD{sub 3} reaction". United States. doi:10.1063/1.4881517.
```

```
@article{osti_22420134,
```

title = {Accuracy of the centrifugal sudden approximation in the H + CHD{sub 3} → H{sub 2} + CD{sub 3} reaction},

author = {Zhang, Zhaojun and Chen, Jun and Liu, Shu and Zhang, Dong H., E-mail: zhangdh@dicp.ac.cn},

abstractNote = {The initial state selected time-dependent wave packet method has been extended to calculate the coupled-channel reaction probabilities with total angular momentum J{sub tot} > 0 for the title reaction with seven degrees of freedom included. Fully converged integral cross sections were obtained for the ground and a number of vibrational excited initial states on a new potential energy surface recently constructed by this group using neural network fitting. As found from a previous study with the centrifugal sudden (CS) approximation, all these initial vibrational excitations investigated in this study enhance the reactivity considerably at a given collision energy, in particular the CH stretch excited state. The energy initially deposited in CH stretch motion is more effective than translational energy on promoting the reaction in the entire energy region, while for CH bending or CD{sub 3} umbrella excitations only at the high collision energy the vibrational energy becomes more effective. Our calculations also revealed that the accuracy of the CS approximation considerably deteriorates with the increase of J{sub tot}, in particular on the threshold energy. The CS approximation underestimates the integral cross sections for all these initial states, albeit not very severely. In general, it works better at high collision energies and for vibrationally excited initial states, with the increase of integral cross section.},

doi = {10.1063/1.4881517},

journal = {Journal of Chemical Physics},

issn = {0021-9606},

number = 22,

volume = 140,

place = {United States},

year = {2014},

month = {6}

}