THEORETICAL STUDIES OF EFFECT OF ELECTRON CORRELATION ON GEOMETRY AND BARRIERS TO INTERNAL-ROTATION IN HYDROGEN-PEROXIDE

The effect of electron correlation on the geometries of the skew, cis and trans conformations of H2O2 and on the heights of the barriers to internal rotation has been investigated by means of ab initio strongly orthogonal geminal (APSG) calculations using a high quality gaussian basis set. The intrapair correlation included in the APSG method accounts for the deficiencies in previous SCF predictions of the equilibrium geometry for H2O2, and with the exception of the OO bond length, which is overcorrected, the calculated geometrical parameters agree well with experimental values. The calculated barriers to internal rotation are little affected by the inclusion of electron correlation and in particular the experimentally poorly characterised cis barrier is predicted to be 35 kJ/mol, supporting the previous best SCF result. Selected calculated one-electron properties for H2O2 are also reported. © 1978.