Thursday, July 29, 2010

Jumping from one surface to another

Many interesting chemical processes involve non-adiabatic processes, i.e., they involve transitions between different potential energy surfaces and thus a break-down of the Born-Oppenheimer approximation. Calculating the rate of such processes (even in "toy" models, let alone full electronic structure theory calculations) is a great challenge.

One of the most stimulating talks I heard last week in Telluride was by Joe Subotnik. He gave a nice review of this problem and the "Tully problems" used as a benchmark.

Strategies for treating the problem with increasing sophistication (and computational cost) are something like:
  • Ehrenfest mean-field dynamics
  • Surface hopping
  • Ehrenfest + decoherence (Prezhdo, Rossky, Schwartz...)
  • Semi-classical dynamics (Miller–Meyer–Stock–Thoss formalism)
  • Partial Wigner transforms (Kapral)
  • Multiple spawning
  • Full nuclear quantum dynamics
A recent J. Chem. Phys. paper by Joe also gives a good overview. This is all stuff I need to get a better handle on ....

1 comment:

  1. If you want to start a schedule of reading & discussion for a series of dynamics papers, I'd be on board.