BAND SPECTRUM AND STRUCTURE OF THE BCl MOLECULE

Abstract

The ¹Π−¹Σ⁺ system of the BCl molecule has been photographed in the sixth order of a 20 ft. grating. The previous interpretation of the vibrational structure by Miescher (5) is slightly modified. The new formula for the Q heads of the B¹¹Cl³⁵ molecule is[Formula: see text]The fine structure of a number of bands has been measured and analysed, leading to the following accurate values for the rotational constants: B′_e = 0.7054 cm.⁻¹, α′_e = 0.00820 cm.⁻¹, B″_e = 0.6838 cm.⁻¹, α″_e = 0.00646 cm.⁻¹. The internuclear distance in the ground state is r″_e = 1.716.10⁻⁸ cm. The molecular constants of BCl are compared with those of the iso-electronic molecules CS, PN, and SiO as well as with those of BBr, BCls, and BBr₃.