The a3Σ+ → X1Σ+ and b3Π → X1Σ+ band systems of SiO and the a3Σ+ → X1Σ+ band system of GeO observed in chemiluminescence

Abstract

Chemiluminescence from SiO and GeO has been produced in a flowing gas system utilizing the reactions Si(3P) + N2O → SiO(b3Π,a3Σ+) + N2 ΔH = −150 kcal/mole Ge(3P) + N2O → GeO(a3Σ+) + N2 ΔH = −130 kcal/mole. An analysis of the chemiluminescence spectrum has shown that the emission originates in the b3Π and a3Σ+ states and terminates in the ground electronic state of SiO. The measured value of the spin–orbit coupling constant for the b3Π state was 75 cm−1. No vibrational constants for either the a3Σ+ or b3Π states could be determined. T0 for the b3Π state was found to be 33 853 cm−1 while that for the a3Σ+ state was found to be 33 409 cm−1. An analysis of the chemiluminescence of GeO was found to originate from the a3Σ+ state and terminate in the electronic ground state. T0 for the a1Σ+ state of GeO was found to be 27 552 cm−1. Good agreement between the experimentally observed vibronic band intensities and those calculated using the Rydberg–Klein method has been obtained.

Vibrational analysis of the 3Π1–X1Σ+ band systems of SiCl+

“…2. Among the possible three branches, the 3111-1C+ subsystem often gives the appearance of having two heads, R and Q: e.g., SiO(b311-XIC+) (17). Therefore, the observed heads in the a3111-XIC+ subsystem are ascribed to R and Q; the Q branch is stronger than the R branch.…”

FTIR Emission Spectra, Molecular Constants, and Potential Curve of Ground State GeO

“…As one of the important oxides of group IVa elements, germanium monoxide (GeO) has been studied extensively, both theoretically (1)(2)(3)(4) and in a variety of experiments, including microwave spectroscopy (5,6), chemiluminescence studies of low-lying electronic states (7)(8)(9), photoelectron spectroscopy (10), electronic absorption (11)(12)(13), and emission (14) spectroscopy, and in matrix isolation (15,16), and gasphase infrared spectroscopy (17). Summaries of early spectroscopic work were reported by Capelle and Brom (9), Huber and Herzberg (18), and Ż yrnicki (14).…”

Infrared absorption of GeNNO isolated in solid Ar

“…The 15 N-isotopic ratios provide further support for the assignments to 1 GeNNO. The isotopic ratio is defined as the ratio of vibrational wavenumber of the specific isotopic variant to that of the naturally abundant species, in this case, species containing 74 Ge, 14 N, and 16 O. Observed isotopic ratios are listed parenthetically in Table I to compare with those derived from quantum-chemical calculations in Table II; they agree satisfactorily with those of 1 GeNNO, with deviations less than 0.0023.…”

“…Vibrational wavenumbers of these species containing one or two 15 N or one 72 Ge were also computed and presented as isotopic ratios in Table II. The isotopic ratio is defined as the ratio of vibrational wavenumber of the specific isotopic variant to that of the naturally abundant species, in this case, species containing 74 Ge, 14 N, and 16 O.…”

“…The reported rate coefficients of the gaseous reaction Ge+ N 2 O range ͑1.2-9.9͒ ϫ 10 −12 cm 3 molecule −1 s −1 near 298 K [11][12][13][14] and ͑5.7-7.6͒ ϫ 10 −12 cm 3 molecule −1 s −1 near 580 K. 13,15 Hager et al 16 and Capelle and Brom, Jr. 17 detected emission from electronically excited states a 3 ⌺ + , b 3 ⌸ 1 , and A 1 ⌸ of GeO, designated GeO ‫ء‬ , from reaction of Ge with N 2 O. Fontijn and Felder reported that the order of GeO ‫ء‬ photon yield was only 10 −4 . 15 To explain these results, they proposed a mechanism involving a preferential reaction of Ge in its 3 P 1 state with N 2 O to form a "reservoir" GeO ‫ءء‬ state, from which the emitting GeO ‫ء‬ states were produced via collision.…”