I am seeking vapor heat capacity for 2-chloroethyl ethyl sulfide (CEES) and phosphonic acid, methyl, dimethyl ester (DMMP). Is there a better forum for this request?
Unless someone (the supplier?) has measured data, I'd recommend estimating Cp for these two components. Group contribution methods are covered in detail in Sherwood, Reid and Prausnitz and other property estimating books.