# The Fundamental Vibration-Rotation Band of Hydrogen Chloride

I. M. Mills, H. W. Thompson, R. L. Williams

## Abstract

The fundamental vibration-rotational absorption band of hydrogen chloride near 3$\cdot$45 $\mu$ has been remeasured using higher resolving power than previously. The wave-lengths of the absorption lines have been determined more precisely, and the isotopic splitting of lines has been completely resolved. The results have provided new and more satisfactory values for the rotational constants B$_{i}$, and the centrifugal stretching constants D$_{i}$, and their relative values for the two isotopic species agree closely with what is to be expected for the difference in mass. The positions of the lines in the pure rotational absorption spectrum have been calculated from the derived data, and agree closely with those recently observed. The bond lengths r$_{e}$ for each isotopic species H$^{35}$Cl and H$^{37}$Cl is found to be 1$\cdot$274$_{4}$ angstrom.