CCL: question on Born-Oppenheimer approx.

[Jun Zhang <coolrainbow . yahoo.cn>]

 Sent to CCL by: Jun Zhang [coolrainbow-*-yahoo.cn]
 Hi everyone:
  This question is quite fundermental. I share the somewhat
  similar opinion with Ulf Ekstrom. For an isolate molecule in
  vacuo, by time-independent SE beyond the BO approximation
  with bound state condition, e.g. CH3OCH3 and C2H5OH, they of
  ourse have the same form of SE and have the same solutions.
  BO approximation, although excellent, does not tell us why
  a particular nuclear configuration can be stable (geometry
  optimization is not the answer since the conception of PES
  is within the framework of BO). In my opinion, the
  introduction of BO approximation can be viewed as a "coarse
  grain" decription of the molecule world, i.e. "unknown" of
  the history of the molecule or the rest of the world. The
  stable existence of a specific configuration, CH3OCH3 or
  C2H5OH, might be traced back to a particular initial
  condition at time t=t0, which has made the solution of SE
  might have some special dynamics properties that the time
  evolution of the configuration is very slow. Another
  possibility is that the condense state of material might
  stabilize the molecule, or we may say that it is those
  molecular configurations which can "survive" or "be robust"
  in the environmant are able to be stationary, or as Ulf
  Ekstrom stated, "pointer state". BO approximation that
  fixes a known nuclear configuration, in my point of view,
  is the reduced description of all other "unknowns"
  Jun Zhang
  Nankai University
  coolrainbow---yahoo.cn