Subject: mean residence times (again)

From: Hannes Loeffler <[email-masked]>
Date: Mon, 27 May 2002 21:44:07 +0200

Hello all,

I recently asked how to calculate mean residence times and got several useful
pointers to the literature.  Now I mostly understand how to implement the
computations myself but still are unsure about some issues.

Obviously, the mean residence time is computed from a correlation function. 
Thus the same assumption applies as for other time correlation functions (or the 
MSD as I recently learned from this list): it is independent(?) of the chosen
time origin and to improve statistics one may average over several time origins
(overlapping windows).  I hope that's right.

Impey et al. introduced a book-keeping value t^star to account for molecules
leaving only temporarily from the region of interest.  Other authors set this
value to zero.  Anyway, I'm still unsure what I should do if such a molecule
leaves for a (much) longer time then t^star and returns after some time.  Should
the residence time correlation function increase again?  Or should this water be
considered as to have never been in the region of interest at the time origin
(in this case the correlation function is strictly decreasing)?

I hope somebody can enlighten me,
Hannes.

-- 
Hannes Loeffler | tel: +43-(0)512-507-5166 | fax: +43-(0)512-507-2714
http://www-c724.uibk.ac.at/staff/loeffler/ | mailto:[email-masked]
Institute for General, Inorganic and Theoretical Chemistry
University of Innsbruck, Austria