Comparison of the Spectra of CaH and CaD
William W. Watson · Physical Review · 1935
The spectrum of calcium deuteride has been photographed at high dispersion with a Ca arc in an atmosphere of heavy hydrogen as a source. Quantum analyses of the $B$ and $C$ systems are presented, and the rotational energy constants and spin doubling of the two states of the $B$ bands are compared with those for CaH. The ratio $\frac{{{B}_{e}}^{i}}{{B}_{e}}$ for the ground state is 0.51337 whereas the ratio of the reduced masses is 0.51276. This represents a decrease of 0.059 percent for the equilibrium internuclear distance in CaD. The spin doubling in the $B ^{2}\ensuremath{\Sigma}$ state of CaD does not show the irregular variation with $K$ found in CaH, and is of magnitude almost exactly in the ratio ${\ensuremath{\rho}}^{2}$ with that of the A-doubling in the $A ^{2}\ensuremath{\Pi}$ state of CaH. Multiple large perturbations occurring in the $C ^{2}\ensuremath{\Sigma}$ state of CaD are described.