# CCL: Entropy calculations for condensed state

*From*: "James Mao" <xjamesmao=gmail.com>
*Subject*: CCL: Entropy calculations for condensed state
*Date*: Mon, 5 Mar 2012 19:52:16 -0500

Sent to CCL by: "James Mao" [xjamesmao|a|gmail.com]
Dear cclers,
I am trying to evaluate the entropy change of a reaction (1,3-cyclohexadiene
-> 1,4-cyclohexadiene). They both are liquid and the experimental data shows
the entropy change is negative, which is reasonable since 1,4-cyclohexadiene has
a higher symmetry.
However calculations for gas phase all show 1,3-cyclohexadiene has a lower
entropy than 1,4-cyclohexadiene (I tried different basis sets and methods). Is
this due to the reason that symmetry factor is not included for a single
molecule calculation in gas state? The arrangements of the molecules in liquid
phase should contribute a large part of entropy, right? As to my problem, is
there any way to evaluate entropy in liquid phase?
Any suggestion will be greatly appreciated.
Best,
James