High-levelab initio versus DFT calculations on (H2O2)2 and H2O2-H2O complexes as prototypes of multiple hydrogen bond systems

✍ Scribed by Gonz�lez, Leticia; M�, Otilia; Y��ez, Manuel

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 199 KB
• Volume: 18
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/(sici)1096-987x(19970715)18:9<1124::aid-jcc2>3.0.co;2-t

✦ Synopsis

The performance of B-LYP, B-P86, B3-LYP, B3-P86, and B3-PW91 density functionals to describe multiple hydrogen bond systems was studied. For this purpose we have chosen the dimers of hydrogen peroxide and the hydrogen peroxide᎐water complexes. The geometries and vibrational frequencies Ž . obtained with a 6-311 q G d, p basis set were compared with those obtained at the MP2 level using the same basis set expansion. The corresponding Ž . dimerization energies were obtained using a 6-311 q G 3df, 2p basis set and Ž . compared with those obtained using the G2 MP2 theory. Red shiftings of the OH donor stretching frequencies were predicted by all approaches investigated; however, in all cases, the DFT values were sizably larger than the MP2 ones. Similarly, the blue shifting of the torsion of the hydrogen peroxide subunit was Ž . larger when evaluated at the DFT level. All functionals reproduced the G2 MP2 relative stabilities of the different local minima quite well. With the exception of the B-LYP and B3-PW91 approaches, all functionals yielded binding energies Ž . which deviated from the G2 MP2 values by less than 0.5 kcalrmol, provided that G2-type basis sets were used and that the corresponding BSSE corrections were included.