The band spectrum of yttrium oxide (YO). With a note on the ScO and LaO Systems

Abstract

Our attention was drawn to these bands during a perusal of the ‘ Collected Papers’ of Eder and Yalenta. Eder* has given measurements of a large number of bands due to yttrium oxide which appear in the flame of a carbon arc when fed with the oxide, chloride, or sulphate of this metal. He gives also some good reproductions of these bands from grating photographs. So far as we are aware, no quantum analysis of this spectrum has hitherto been published. In the present paper we give new data for the band heads which we have obtained from photographs taken in the first order of a 21-foot Rowland grating. About 100 heads have been measured, each having been evaluated from three independent plates. On the whole there is reasonably good agree­ment with Eder’s measurements. The experimental procedure found most satisfactory was to burn a carbon arc with 10-15 amps., the positive being cored and packed with a mixture of yttrium oxide and a little sodium carbonate. In the extensive yellow flame which rose some 2 or 3 inches above the arc the bands of yttrium oxide were strongly developed, and good grating photographs were obtainable with from 15 to 30 minutes exposure. The band systems of the YO molecule are of considerable interest when con­sidered in relation to those of the scandium oxide and lanthanum oxide mole­cules. The series ScO, YO, LaO should have similar external electronic structures* and analogous band systems may, therefore, be anticipated. The systems of scandium oxide have been only partially recorded. Mecke has analysed but one system completely. The systems of lanthanum oxide have recently been dealt with by Meckel and Jevons.§ The latter gives a good summary of these in his paper. During the course of the present investigation of yttrium oxide a brief summary of work by Meggers and Wheeler was published in the ‘Bulletin of the American Physical Society ’|| on the band spectra of all three oxides. We hope that this information may subsequently be published in full. The published summary is sufficient to show that there is—as one would anticipate—a very close resemblance between the band systems of these three molecules.