P. Hassanzadeh et Kk. Irikura, NEARLY AB-INITIO THERMOCHEMISTRY - THE USE OF REACTION SCHEMES - APPLICATION TO IO AND HOI, The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 101(8), 1997, pp. 1580-1587
Reaction energetics from ab initio calculations are almost always comb
ined with experimental data to derive enthalpies of formation. Some po
pular strategies are discussed, and a simple criterion is suggested fo
r estimating the accuracy to be expected from using an arbitrary react
ion, We recommend using more than one reaction scheme whenever possibl
e and suggest how the results from different reactions may be combined
in a weighted average. The uncertainties of the derived values can be
estimated from the averaging procedure and by comparing the results o
btained using different basis sets and treatments of electron correlat
ion. As examples, we compute the gas-phase thermochemistry for IO-, IO
, IO+, and HOI. As a check, analogous calculations are also done for t
he corresponding bromine species. Finally, we recommend that appropria
te experimental data be exploited whenever they are expected to be mor
e accurate than their theoretical counterparts. While compiling the au
xiliary data to support these calculations, we found that recent measu
rements require that the experimental enthalpies of formation of many
molecules be revised. We present values for HOCl, HOBr, Cl2O, and Br2O
.