b1Σ+ and a1Δ emissions from group VI-VI diatomic molecules: b0+ → X10+, x21 emissions of TeO and TeS

Negative ion photoelectron spectroscopy of teo−

“…In case "c" the X 3Z-state becomes X O+ and X I*, a 'A becomes a 2, and b lx+ is b O+. As mentioned earlier TeO possesses a relatively large ground state spin-spin splitting which has been determined to be 789 cm-l [8]. By comparison, little is known about the magnitude of the spin-orbit splitting in the negative ion TeO-.…”

“…In contrast to these, however, TeO is believed to be coupled according to Hund's case "c" [8]. In case "c" the X 3Z-state becomes X O+ and X I*, a 'A becomes a 2, and b lx+ is b O+.…”

“…The consequence of this is that the X 1 *(II') vibrational levels occur within a few wavenumbers of the X O+(u' t 1) vibrational levels and that, at an instrumental resolution of =30 meV (240 cm-l), transitions to these levels are unresolved. Also, since the X 1 f. state is doubly degenerate transitions to it are twice as strong as are those to the lower energy [8] X0+ state. If the spin-orbit splitting in the TeO-negative ion is as large as we have assumed, then its upper spin-orbit state is not expected to be significantly populated, and those transitions that do appear due to the upper state will be shifted to the high electron kinetic energy side of the main spectral profile.…”

“….n2 have a ratio of the term energies for their a lA and b lx+ states of 0.55 f 0.05. Winter et al [8] have measured the b O+ + XI O+ transition energy in TeO to be 9966 cm-l. This predicts that the origin peak of the a 2 state will lie at a c.m.…”

“…Subsequent spectroscopic work has included emission studies in the visible and in the near-ultraviolet [3-51, absorption in the near-ultraviolet [6], matrix-isolation studies in the infrared [7], and chemiluminescence in the near-infrared [8]. TeO is distinguished from other group VIB diatomic oxides by its unusually large spin-spin splitting in the ground state [8,10]. Thermochemical data on TeO are also available [ 1 l-l 31.…”