Atomization enthalpy and enthalpy of formation of gaseous Si4 from mass spectrometric equilibrium measurements

Abstract
Recent spectroscopic and theoretical investigations have allowed us to calculate new thermal functions for the Si4 molecule. These thermal functions have been combined with new and with reevaluated mass spectrometric data in obtaining an atomization enthalpy of ΔHa,0=1160±22 kJ mol−1 and an enthalpy of formation of ΔHf,0=643±22 kJ mol−1. The experimental results are compared to MP4/6–31G* and G2 predictions.