CCL: Entropy calculations for condensed state

 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