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

The accurate ground‐state potential energy surface of hydrogen peroxide, H₂O₂, 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 H₂O₂, D₂O₂, and HOOD isotopologues were predicted, and the experimental vibrational fundamental wavenumbers were reproduced to 1 cm^?1 (“spectroscopic”) accuracy. © 2012 Wiley Periodicals, Inc.