THE POTENTIAL ENERGY FUNCTION OF $CS_{2}$ DERIVED FROM ROVIBRATIONAL DATA
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Date
1994
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Ohio State University
Abstract
We have derived the potential energy surface of the $\tilde{X}^{1}\Sigma^{+}_{g}$ electronic state of $CS_{2}$ by adjusting it in a fitting to experimental rotation-vibration data. Using a variational approach and the Morse Oscillator Rigid Bender (MORBID) Hamiltonian, with a basis set composed of Morse oscillator stretching functions and rigid bender bending functions, we were able to fit twenty six vibrational band origins, up to $5000 cm^{-1}$, and forty rotational level separations with $J < 6$; we obtain a root mean square deviation of $0.58 cm^{-1}$ for the vibrational energies. The large masses of the terminal sulphur atoms lead to difficulties in basis set convergence because of large and unavoidable bend-stretch coupling in the kinetic energy operator. This effect has not been observed in previously studied hydrides such as $CH_{2}, H_{2}O, H_{2}S_{1}$, and $H_{2}Te$.
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Author Institution: Herzberg Institute of Astrophysics, National Research Council of Canada; Physikalisch-Chemisches Institut, Justus-Liebig Universit\""{a}t Gaessen