In this theoretical work, the authors consider the geometrical, electronic and energetic properties of some lithium and beryllium derivatives. The standard heats of formation of these compounds have been calculated at the MP4=SDTQ/6-31+G(2/b df/,/b p/)//MP2=FULL/6-31G(/b d/,/b p/) level. The values obtained at this level of the theory are also compared with the heats of formation deduced from a composite procedure in which it is assumed that some corrections can be treated separately and combined in an additive manner. They find that the values determined with the complete 6-31+G(2/b df/,/b p/) basis set are the more accurate.
Sana, M., & Leroy, G. (1990). Theoretical thermochemistry of some LiXH/sub n/ and BeXH/sub n / compounds. Theoretica Chimica Acta, 77(6), 383-394. https://doi.org/10.1007/BF01374529 (Original work published 1990)