THE FAR INFRARED SPECTRUM OF $H_{2}O_{2}$. FIRST OBSERVATION OF THE STAGGERING OF THE LEVELS
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Date
1989
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Publisher
Ohio State University
Abstract
High resolution spectra of $H_{2}O_{2}$, recorded by means of Fourier transform spectroscopy between 30 and $460 cm^{-1}$ have been analysed leading to the determination of the rotational levels of the torsional states $(n, \tau)$ for $n=0,1,2,3$. To reproduce these energy levels. Watson type Hamiltonians have been used and it has been possible to observe the staggering of the levels due to the cis-barrier for n=2 and 3. The torsional hand centers have then been fitted using a torsional Hamiltonian of the form $\left\{B_{\gamma\gamma},J^{2}_{\gamma}\right\} + V(\gamma)$ with the potential energy function $V(\gamma)$ written as $V(\gamma) = V_{1} \cos 2\gamma + V_{2} \cos 4\gamma + V_{3} \cos 6\gamma + V_{4} \cos 8\gamma$ where the torsional coordinate $2\gamma$ is the dihedral angle defining the relative position of the two O-H honds. The potential function constants obtained are $\begin{array}{ll}V_{1} = 1036.97 \pm 23.1 cm^{-1}, &V_{2} =657.53 \pm 5.2 cm^{-1}.\\ V_{3} = 50.89 \pm 3.3 cm^{-1} , V_{4} = 2.524 \pm 0.83 cm^{-1}\end{array}$$ corresponding to the barrier heights $V_{trans} = 387.07 \pm 0.20 cm^{-1}\quad V_{CIs} = 2563 \pm 70 cm^{-1}$$ and to potential energy minima located at $2\gamma = 111.9. \pm 0.4$ from the cis-configuration. It is also shown that the rotational constants derived through the fit of the experimental rotational levels cannot be reproduced using a model which does not take into account the vibrational corrections.
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Author Institution: Laboratoire de Physique Mol\'eculaire et Atmosph\'erique., Tour 13. Universit\'e Pierre et Marie Curie et CNRS; Herzberg Institute of Astrophysics, NRC, Ottawa; Herzberg Institute of Astrophysics, IROE - CNR, Via Panciatichi 64,