Predissociation Phenomena in Spectra of some Diatomic Molecules

Abstract

IN emission at low pressure, the C-band (0,0) of strontium hydride is cut off above R(18) = 26,549 cm.^-1, the upper level of which (C, v = 0, J = 19) lies 27,776 cm.^-1 above the ground-level N, v = 0, J = 0. In spite of this, Watson and co-workers found no traces of the (1,0) band in emission at low pressure, though the levels C, v = 1, J = 1 to J = 6 lie only 27,620 to 27,770 cm.^-1 above this ground-level (cf. More and Cornell¹, table 1). Thus the statement of More and Cornell (p. 808) that the (1,0) band “lies far beyond the predissociation limit at Kâ = 19 in the (0, 0) band” must be incorrect. Consequently the predissociation occurs at an energy-level at least ˜150 cm.^-1 lower in C, v = 1 than in v = 0. Previously Herzberg² has found similar cases in the P₂ and N₂ molecules.