| Autor: |
Judith B. Rommel, Yanchuan Zhang, Marko T. Cvitaš, Stuart C. Althorpe |
| Jazyk: |
angličtina |
| Rok vydání: |
2014 |
| Předmět: |
|
| DOI: |
10.1039/c4cp03235g |
| Popis: |
We obtain a shallow-tunnelling correction factor for use with Wigner-Eyring transition- state theory (TST). Our starting point is quantum transition state theory (QTST), which approximates the accurate quantum rate as the instantaneous flux through a delocalised transition-state ensemble of ring-polymers. Expanding the ring-polymer potential to second order gives the well-known Wigner tunnelling- factor which diverges at the cross-over temperature between deep and shallow tunnelling. Here, we show how to remove this divergence by integrating numerically over the two softest ring-polymer normal modes. This results in a modified Wigner correction factor involving a one-dimensional integral evaluated along a straight line on the potential energy surface. Comparisons with accurate quantum calculations indicate that the newly derived correction factor gives realistic estimates of quantum rate coefficients in the shallow- tunnelling regime. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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