Millimeter/Submillimeter-Wave Spectrum of the First Excited Torsional State in HOOH

The millimeter and submillimeter (mm/submm)-wave spectrum of hydrogen peroxide has been extended to include the first excited torsional state, n = 1. The 135 newly assigned rotational transitions within the n = 1 torsional state range from Ka = 2 to 9 and up to J = 30. Sixty-seven new observations in n = 0, which include rotational quantum numbers up to J = 47 and Ka = 5, supplement the previously measured 349 torsional ground state transitions. All of the observed mm/submm-wave transitions within the n = 0 and 1 torsional states, as well as recent infrared data, have been fit simultaneously to their respective experimental uncertainties using a Watson-type Hamiltonian for each of the torsional states, τ. A Fermi interaction between the torsional levels in n = 0, 1, and 2 has been included