Rotational Structure in the A²Σ⁺, B²Σ⁺, and a⁴Σ⁻ – X²Π Transitions of GeF

Abstract

Rotational analysis of over 50 sub-bands of three emission transitions of 74GeF has given vibrational and rotational constants for the four lowest-lying electronic states of GeF. One of these is a 4Σ− state in Hund's case (a), where all four spin components have been identified. Extensive perturbations between this 4Σ− state and the B2Σ+ state have been analyzed in detail: the two states appear to interact mainly by a second-order mechanism through the so far uncharacterized σπ22Σ+ state, but the surprisingly large J dependence of the perturbation matrix element suggests that another mechanism, possibly involving the ground state, may contribute. Further perturbations, where the lines show an unusual intensity enhancement, appear in those sub-bands with B2Σ+ ν = 4 as upper state.

The interacting B 4Σ− and d 2Π states of CrN: A laser induced and dispersed fluorescence study

“…Spectra of 2 ⌸← 4 ⌺ Ϫ transitions have been observed and analyzed in several molecules. 27,28 The appearance of d 2 ⌸←X 4 ⌺ Ϫ bands in CrN is very similar to that of the A 4 ⌸←X 4 ⌺ Ϫ transition, except only two spin-orbit components are present. Twelve branches can be expected for each subband.…”

“…Matrix elements for this Hamiltonian have been given by Cheung, Taylor, and Merer. [26][27][28] Our fitting process was similar to that used successfully to analyze bands in the corresponding A 4 ⌸←X 4 ⌺ Ϫ system. Parameters for the lower state were fixed at the values obtained in the A -X analysis; our Franck-Condon analysis provided an estimate for the rotational constant B in the upper state; and trial values of ␥Ј and Ј were used.…”

“…27 The d 2 ⌸ 3/2 ←X 4 ⌺ Ϫ (0,0) band was analyzed first. Its observed line positions and assignments are shown in Fig.…”

“…The ␥ parameter is actually an effective one since it includes not only the first order contribution from spinrotation interaction H SR , but also second-order contributions principally from coupling to 4 ⌸ states (H SO ϫH ROT ). 27,31 The A 4 ⌸ state lies much closer to the B 4 ⌺ Ϫ state than it does to the X 4 ⌺ Ϫ state and a greater second-order contribution to ␥(B 4 ⌺ Ϫ ) is to be expected. The contribution from ͑second order͒ spin-orbit coupling to 2 ⌺ is not significant at our experimental resolution and the parameters ␥ 1 and ␥ 2 in Table V were then taken to be identical.…”

Molecules for Materials: Structures, Thermochemistry, and Electron Affinities of the Digermanium Fluorides Ge2Fn/Ge2Fn- (n=1-6): A Wealth of Unusual Structures

“…The study of these fluorides has recently become an active research area. Besides experimental studies on silicon fluorides6–8 and disilicon fluorides,9–11 investigations, including IR and Raman spectroscopy, photoelectron spectroscopy, structure determination, electron affinities, and dissociation energies, have been reported for GeF,12–14 GeF 2 ,15–18 GeF 3 ,19–20 GeF 4 ,21–23 GeF 5 ,24–26 Ge 2 F 4 ,27–28 and Ge m F n ( m =1–3, n =1–11) 29. However, some of the experimental data from these studies are incomplete, and for several species it was difficult to carry out experimental studies.…”