Theoretical investigation of isomerism in dimers (HBO)2, (HBS)2, (HAlO)2 and (HAlS)2

Using several basic sets and taking into account electron correlation, non-empiric calculations of the structure and relative stability of (HBO)2, (HBS)2, (HAlO)2 and (HAlS)2 dimers were made. Isomers of (HA)2Y2 structure (A = B, Al; Y O,S) have the highest stability, isomers of A2(YH)2 structure are more than 20 kcal/mol less stable. High potential barrier hampers transition frome one isomer to the other. Stability of (HA)2Y2 dimer to decomposition into monomers (HAY+HAY) increases in the series HBS-HBO-HAlS-HAlO