Reduced Dimension Rovibrational Variational Calculations of the S_1 State of C_2H_2 Conference Paper uri icon


  • The bending and torsional degrees of freedom in S_1 acetylene, C_2H_2, are subject to severe vibrational resonances and rovibrational interactions, which result in the low-energy vibrational polyad structure of these modes. As the internal energy approaches that of the barrier to cis-trans isomerization, these energy level patterns undergo further large-scale reorganization that cannot be satisfactorily treated by traditional models tied to local equilibrium geometries. Experimental spectra in the region near the cis-trans transition state exhibit these complicated new patterns. In order to rationalize our near-barrier observations and predict the detailed effects of cis-trans isomerization on the rovibrational energy structure, we have performed reduced dimension rovibrational variational calculations of the S_1 state. Our calculation uses a high accuracy ab initio potential surface and a fully …

publication date

  • June 1, 2013