Structure and bonding of weak hydrogen peroxide complexes

The B3LYP and MP2 theoretical levels, with the 6-311 + G(3df,2p) basis set, have been used to characterize different vdW complexes, between hydrogen peroxide (HP) and nitrogen (4, 8 and 12), helium (1, 5 and 9), neon (2, 6 and 10) and argon (3,7 and 11). Additional MP4 and CCSD(T) calculations were also performed to test the validity of the MP2 results, for the HP... He structures. Cyclic TSs and linear or cyclic minima were found on their corresponding PESs. The atoms-in-molecules theory (AIM) was also used to analyze the intermolecular interactions and the possible cyclic or linear nature for all the complexes. In addition, the binding energy (DeltaE(b)) was corrected for the BSSE by the counterpoise (CP) method. Moreover, calculations were performed also on the BSSE-corrected PESs. The MP2 results yielded very weak BSSE corrected DeltaE(b) (-0.1 to -6.4 kJ mol(-1) range). However, the B3LYP method gave positive DEb values for some complexes, resulting in an incorrect energy description. Structural differences were also found on their corresponding BSSE-corrected PESs compared to the uncorrected ones. (C) 2002 Elsevier Science B.V. All rights reserved.