Atomic and molecular absorption spectra of indium in air-acetylene flame

Abstract

Absorption spectra of both atomic and molecular species in the air-acetylene flame, which are produced when the aqueous solutions of indium dissolved in HNO 3, HF, HCl, HBr and HI were aspirated into the flame, have been investigated in the u.v. region. Numerous atomic absorption lines of indium have been observed in the absorption spectra. Most of these lines were previously listed only as emission lines. Those atomic lines have been ascribed to the electronic transitions from the ground states of 5 p 2 P 1 2 0 and 5 p 2 P 3 2 0 to the excited states such as ls 2 S 1 2 , md 2 D 3 2 , nd 2 D 5 2 , 4 p 2 4 P 1 2 , 4 p 2 4 P 3 2 and 4 p 2 4 P 5 2 , respectively, where 13 ⩾ l ⩾ 6 and 14 ⩾ m, n ⩾ 5. The molecular absorption bands for InF, InCl and InBr in the airacetylene flame have been also observed near 234 nm, 267 nm and 282 nm, respectively, as the electronic transition of 1Σ + → 1Π 1 Those absorption bands show fine structures due to the molecular vibrations. The spectral parameters for the molecular vibrations have been obtained from the simulations of the observed spectra. The molecular absorption band for InI was not observed because of the decomposition of the molecule in the flame. In addition, the molecular absorption band for InO has been observed near 273 nm and those for NO near 205 and 215 nm.