CCL: Gamess calculation of chloro-fluoro-compounds

 Hi CCL'ers,
 In order to calculate transition states of several reactions involving C2
 chloro-fluoro-compounds and the standard heats of formation
 of chloro-fluoro-compounds, I am using GAMESS US.
 For the calculating of both TS and standard heats of formation,
 I have used a STO NGAUSS=3 basis  and a SBK NPFUNC=1
 NDFUNC=1 basis
 Both basis's give poor results for the standard heat of formation
 for fluorine containing molecules
 Does anyone have experience with the calculation of chloro-fluoro-
 compounds and is it possible to advise me for the selection of
 a better basis for my calculations.
 Thank you in advance
 Steven Brillant
 sb : at :
 PhD student
 Laboratorium voor Petrochemische Techniek
 University of Ghent