Application of the HEAT Protocol on Select Commonly Studied Chemical Species

The High accuracy extrapolated ab initio thermochemistry (HEAT) protocol has been applied to a variety of commonly studied chemical species in order to obtain the thermodynamic energy values of their relevant states – primarily ground states but not necessarily. The work aims to extend the growing list of molecules already treated by the protocol, computed purely from theoretical standpoint without appeal to empiricism, for the purpose of complementing the experimental thermochemical values and predicting thermodynamics where measurement becomes difficult. Among the predictions are that methylene ground state is triplet, lower in energy than the singlet state by 37.6533 kJ/mol; the trans-conformer of formic acid is 16.917 kJ/mol lower in energy than the cis-conformer; and that the true ground state of Si3 is singlet, 1.0008 kJ/mol lower in energy than the triplet state.