The emission spectrum of Selenium monoxide

Abstract

The emission spectrum of Se0 was excited in an electrode-less discharge tube containing Selenium dioxide powder by means of a high power microwave generator. Two new band systems of Se0 in the photographic infrared region 10 780 - 9490 Å consisting of 46 bands degraded to longer wavelengths have been observed for the first time. The vibrational analysis of one band system which consists of several double-headed bands shows that it arises from the forbidden transition b ¹Ʃ⁺ - X ³Ʃ⁻ . The double-headed bands have been analyzed as belonging to the ¹Ʃ⁺ - X ³Ʃ⁻(F₁) and ¹Ʃ⁺ - X ³Ʃ⁻(F₂,F₃) sub-systems. The separations between the corresponding band heads of these two sub-systems are consistent with the expected value of ⁻2λ , λ (= 86.4 cm⁻¹) being the splitting constant of the ³Ʃ⁻ state derived by Barrow and Deutsch (1963) from a detailed rotational analysis of the B ³Ʃ⁻ - X ³Ʃ⁻ system of Se0. The vibrational assignments are confirmed by the observed isotope band heads of ⁸²Se0, ⁸⁰Se0, ⁷⁸Se0, and ⁷⁶Se0. The second band system which consists of a single sequence of bands in the region 10 780 - 10 500 Å is tentatively assigned to the probable transition a(¹∆) - X ³Ʃ⁻ of Se0. -- The known emission spectrum of Se0 in the far ultraviolet region 2490 - 1930 Å was photographed and a re-analysis of the bands has been presented. The re-analysis includes a fairly complete vibrational analysis of three band systems, c(¹Ʃ⁺) - b(¹Ʃ⁺), C(³π) - X ³Ʃ⁻ and D(³Ʃ⁻) - X ³Ʃ⁻ and a tentative vibrational analysis of two brief systems x₂ - x₁ and y₂ - y₁. The lower state of the c(¹Ʃ⁺) - b(¹Ʃ⁺) system is found to be the upper state of the b(¹Ʃ⁺) - X ³Ʃ⁻ system mentioned above. -- The constants of ⁸⁰Se0 derived from these vibrational analyses are as follows (the constants for the X state are those derived by Barrow and Deutsch, 1963): -- [table in abstract is omitted]