Journal article
Electronic Free Energy Surface of the Nitrogen Dimer Using First-Principles Finite Temperature Electronic Structure Methods
The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, Vol.127(32), pp.6842-6856
08/03/2023
DOI: 10.1021/acs.jpca.3c01741
Appears in UI Libraries Support Open Access
Abstract
We use full configuration interaction and density matrix quantum Monte Carlo methods to calculate the electronic free energy surface of the nitrogen dimer within the free-energy Born–Oppenheimer approximation. As the temperature is raised from T = 0, we find a temperature regime in which the internal energy causes bond strengthening. At these temperatures, adding in the entropy contributions is required to cause the bond to gradually weaken with increasing temperature. We predict a thermally driven dissociation for the nitrogen dimer between 22,000 to 63,200 K depending on symmetries and basis set. Inclusion of more spatial and spin symmetries reduces the temperature required. The origin of these observations is explored using the structure of the density matrix at various temperatures and bond lengths.
Details
- Title: Subtitle
- Electronic Free Energy Surface of the Nitrogen Dimer Using First-Principles Finite Temperature Electronic Structure Methods
- Creators
- William Z. Van Benschoten - University of IowaHayley R. Petras - University of IowaJames J. Shepherd - University of Iowa
- Resource Type
- Journal article
- Publication Details
- The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, Vol.127(32), pp.6842-6856
- DOI
- 10.1021/acs.jpca.3c01741
- ISSN
- 1089-5639
- eISSN
- 1520-5215
- Publisher
- American Chemical Society
- Grant note
- DOI: 10.13039/100006151, name: Basic Energy Sciences, award: DE- SC0021317, DE-AC02-05CH11231
- Language
- English
- Date published
- 08/03/2023
- Academic Unit
- Chemistry
- Record Identifier
- 9984453331702771
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