MICROWAVE SPECTRA OF $NaBH_{4}$ AND $KBH_{4}$ IN EXCITED VIBRATIONAL STATES
Loading...
Date
1996
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
We have observed two sets of vibrational satellites for each of $NaBH_{4}$ and $KBH_{4}$ and have assigned them to the non-degenerate alkali metal-boron stretching state and to the degenerate $BH_{4}$ bending (or internal rotation) state. The observed transitions were $J=11 <- 10$ up to $J=20 <- 21$ up to $J=28 <- 27$ for the two molecules, respectively. The satellites of $NaBH_{4}$ are quite anomalous; the set of the non-degenerate state extends to higher frequency as K increases, whereas the other set of the degenerate state spreads to lower frequency somewhat more widely than the ground spectrum does. We have analyzed both sets of the vibrational satellites simultaneously using $C_{3v}$ symmetric-top rotational wavefunctions as bases and a vibration-rotation $Hamiltonian.^{a}$ In the case of $NaBH_{4}$, a strong Coriolis interaction was found to affect even small K levels and allowed us to determine not only B, $D_{j}$, $D_{jk}$, and other minor constants, but also the $A$ rotational constants, the difference between the two band origins $W$, and the second-order and the first-order Corilis interaction parameters. On the other hand, the Coriolis interaction perturbed only high-$K$ states of $KBH_{4}$, and thus the $A$ rotational constants and the first-order Coriolis coupling constant could not be derived from the observed spectrum. Therefore, these constants were fixed to ab initio values in the analysis. In addition, $D_{jk}$ of the A state was found to strongly correlate with $W$. The atandard deviation of the fit was, or even smaller than, 0.13 and 0.17 MHz, respectively for $NaBH_{4}$ and $KBH_{4}$.A part of this work was supported by REFR (Pr. n95-03-08081a).
A part of this work was supported by RFFR (Pr.N95-03-08081a).
A part of this work was supported by RFFR (Pr.N95-03-08081a).
Description
$^{a}$Y Kawashima and E.Hirota, J. Mol. Spectrosc. 153, 466 (1992).
Author Institution: Department of Chemical Technology, Kanagawa Institute of Technology; The Graduate University for Advanced Studies, Kanagawa Institute of Technology; Physics Department, Tomsk State University
Author Institution: Department of Chemical Technology, Kanagawa Institute of Technology; The Graduate University for Advanced Studies, Kanagawa Institute of Technology; Physics Department, Tomsk State University