Accurate ab initio potential energy surface and vibration-rotation energy levels of hydrogen peroxide.

The accurate ground-state potential energy surface of hydrogen peroxide, H(2)O(2), has been determined from ab initio calculations using the coupled-cluster approach in conjunction with the correlation-consistent basis sets up to septuple-zeta quality. Results obtained with the conventional and explicitly correlated coupled-cluster methods were compared. The core-electron correlation, scalar relativistic, and higher-order valence-electron correlation effects were taken into account. The adiabatic effects were also discussed. The vibration-rotation energy levels of the H(2)O(2), D(2)O(2), and HOOD isotopologues were predicted, and the experimental vibrational fundamental wavenumbers were reproduced to 1 cm(-1) ("spectroscopic") accuracy.