The H2S Spectrum around 0.7 μm

The overtone spectrum of H₂S has been recorded by intracavity laser spectroscopy in the 14100–14400 cm⁻¹spectral region. The rovibrational analysis was performed allowing one to assign not only lines involving the pair of interacting states {(402), (303)} ({(60⁺, 0), (60⁻, 0)} in local mode notation), but also lines involving the interacting states {(322), (223)} ({50⁺, 2), (50⁻, 2)} in local mode notation). Indeed, apart from the strong H₂₂interactions that link the rotational levels of the states (60^±, 0) on the one hand, and the rotational levels of the states (50⁺, 2) on the other hand, we observe that the rotational levels of the two pairs of states interact strongly through anharmonic and Coriolis-type resonances. These resonances transfer intensity to lines involving the (50⁺, 2) pair of states. Altogether 80 rotational upper-state levels have been observed and reproduced satisfactorily using an Hamiltonian matrix that takes explicitly into account the various interactions and assumes the same vibrational energy and rotational constants for the two components of the local mode pairs. The following band centers have been obtained: ν₀(60⁺, 0) = 14291.122 cm⁻¹and ν₀(50^±, 2) = 14284.705 cm⁻¹. Finally a local mode-type behavior is evidenced by the values of the Hamiltonian constants, and refined vibrational local mode parameters are obtained.