Thursday, May 30, 2013

Quantum effects in condensed phase chemistry

I am looking forward to attending a workshop on Quantum effects in condensed phase systems at the Telluride Science Research Centre in July.
I thank Scott Habershon and Tom Markland for organising what looks like a great meeting. I don't normally do the crazy thing of flying to USA for just one week, but I think this meeting should be worth it.

Much of chemistry is "classical" in the sense that it can be described by semi-classical dynamics of the nuclear degrees of freedom moving on potential energy surfaces that can be calculated in the Born-Oppenheimer approximation.
But, there are important exceptions.

I list below some of the quantum nuclear effects that need to be considered. They are listed roughly in the order of increasing exoticness and decreasing frequency of attention they receive.
  • zero-point energy
  • tunneling
  • non-adiabatic, breakdown of the Born-Oppenheimer approximation
  • interference
  • entanglement (of nuclear and electronic degrees of freedom)
  • geometric (Berry) phases
  • collective coherent effects
These effects can all be present in small molecules in the gas phase.
A key question is how are the above effects modified in a condensed phase environment (e.g. a solvent, glass, or protein)?
Generally, interaction with the many degrees of freedom of the environment will decohere the small molecule degrees of freedom and reduce the quantum effects.

Here are some big questions.
Are there any instances where the environment can 
-enhance any of above quantum effects?
-lead to qualitatively new effects (e.g. associated with collective degrees of freedom) that are absent in the gas phase?

1 comment:

  1. I did not know the forth, sixth and seventh item of the quantum effects. Thanks!