The heats of formation of SiCln+, for n = 1–4

The heats of formation of SiCln and SiCln+, for n = 1–4, have been determined using the G2(B3LYP/MP2/CC) approach. The results for the neutral systems are in very good agreement with previous work. High level calibration calculations allow us to refine the G2(B3LYP/MP2/CC) values. While the computed and experimental IPs of SiCl4 agree, the calculations show that the adiabatic IP is about 7 kcal/mol smaller than the accepted value. The temperature dependence of the heat of formation, heat capacity, and entropy are computed for 300 to 4000 K and fit to a polynomial.