ROTATIONAL SPECTRA OF $PH_{3}$ MOLECULES IN THE FIRST EXCITED VIBRATION STATES $v_{2}$ AND $v_{4}$
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Date
1954
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Ohio State University
Abstract
Improved measurements on the rotational spectrum of $PH_{3}$ have recently been reported by Stroup, Oetjen, and $Bell.^{1}$ In addition to the usual rotation lines certain much weaker lines are also found. These may be classified into two series, one with a $B^{(xx)}$ value ($B^{(xx)}$) being one of the two equal reciprocals of inertia) greater than that for the normal vibration state and another with a $B^{(xx)}$ value smaller than that for the normal vibration state. These lines may be interpreted as arising from rotation of the $PH_{3}$ molecules in the first excited vibration states of $v_{2}$ and $v_{4}$. These levels perturb each other through Coriolis interaction. The magnitude of the perturbation is proportional to a constant $2(\zeta_{2,4}^{(x)}{B}^{(xx)})^{2}/\delta$, where $\zeta_{2,4}^{(x)}$ is the Coriolis coupling factor and $\delta$ is the frequency interval between $v_{2}$ and $v_{4}$. This constant may be estimated from the work of McConaghie and $Nielsen^{2}$ to be about $0.1 cm^{-1}$. This constant may also be estimated from the differences between the $B^{(xx)}$ values for the molecule in these two states, as revealed by the two sets of lines, and the $B^{(xx)}$ value of the molecule in the normal vibration state. It is found that the value of $2(\zeta_{2,4}^{(x)}{B}^{(xx)})^{2}/\delta$ estimated from the rotation spectra of $PH_{3}$ agrees well with the value estimated from the vibration-rotation spectrum.
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$^{1}$R. Stroup, R. A. Oetjen, E. E. Bell, J. O. S. A., 43:1096 (1953) $^{2}$ V. M. McConaghie and H. H. Nielsen. J. Chem. Phys. 21:1836 (1953)
Author Institution: Department of Physics and Astronomy, The Ohio State University
Author Institution: Department of Physics and Astronomy, The Ohio State University