Isotope Effect in the Spectrum of Cadmium Hydride

Abstract

IN an earlier paper¹, I dealt with the structure of different band systems in the spectrum of cadmium hydride. In several respects, however, my analysis suffered from incomplete resolution of the spectrum, especially regarding the isotope splitting of the band lines. Recently I repeated the investigation, using a large concave grating in the third order (0.6 A./mm.). Much work was devoted to the analysis of an extensive system ²∑* ²∑, covering a wide range of vibrational levels (v′= 0 to 13, v″ = 0 to 6) and thus forming a favourable case for an examination of the isotope effect. The band lines are here split into components belonging to Cd (114, 112, 110, 116), already known from the work of Aston.² Besides this, faint components appear belonging to isotopes Cd (118, 108), which have not been reported before. These components were found in every rotational line group of a great number of bands, falling exactly in the position calculated (± 0.02 cm.^-1). I was not able to detect the components of the odd isotopes Cd (111, 113), due to their positions between the intense lines of Cd (110, 112, 114). Only in favourable cases could a diffuse blackening be distinguished between the components of Cd (110, 112), which may be related to Cd (111).