# CCL: gas phase entropy

*From*: "Pierre Archirel"
<pierre.archirel.],[.u-psud.fr>
*Subject*: CCL: gas phase entropy
*Date*: Wed, 21 Mar 2012 11:02:03 -0400

Sent to CCL by: "Pierre Archirel" [pierre.archirel^u-psud.fr]
Dear colleagues,
I wish informations on the calculation of gas phase entropies, namely:
1- are the tabulated measured values accurate? In one case (acetonitrile) they
are obtained from the addition of condensed phase entropies and vaporisation
entropy... Is this general? Is the direct measurement impossible?
2- what is the accuracy of the usual calculations, i.e. Sackur-Tetrode, rigid
rotor and harmonic analysis? Is there some work comparing methods, bases,
anharmonicities, etc?
Thanks in advance,
Pierre Archirel
LCP, Universite Paris-Sud, Orsay