Details

Autor(en) / Beteiligte

• Escartín, J M
• Romaniello, P
• Stella, L
• Reinhard, P-G
• Suraud, E

Titel

On transition rates in surface hopping

Ist Teil von

• The Journal of chemical physics, 2012-12, Vol.137 (23), p.234113-234113

Ort / Verlag

United States: American Institute of Physics

Erscheinungsjahr

2012

Quelle

MEDLINE

Beschreibungen/Notizen

• Trajectory surface hopping (TSH) is one of the most widely used quantum-classical algorithms for nonadiabatic molecular dynamics. Despite its empirical effectiveness and popularity, a rigorous derivation of TSH as the classical limit of a combined quantum electron-nuclear dynamics is still missing. In this work, we aim to elucidate the theoretical basis for the widely used hopping rules. Naturally, we concentrate thereby on the formal aspects of the TSH. Using a Gaussian wave packet limit, we derive the transition rates governing the hopping process at a simple avoided level crossing. In this derivation, which gives insight into the physics underlying the hopping process, some essential features of the standard TSH algorithm are retrieved, namely (i) non-zero electronic transition rate ("hopping probability") at avoided crossings; (ii) rescaling of the nuclear velocities to conserve total energy; (iii) electronic transition rates linear in the nonadiabatic coupling vectors. The well-known Landau-Zener model is then used for illustration.