The <i>a</i>3Σ+ → <i>X</i>1Σ+ and <i>b</i>3Π → <i>X</i>1Σ+ band systems of SiO and the <i>a</i>3Σ+ → <i>X</i>1Σ+ 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.