The electronic band systems of ¹²C¹⁶O⁺

Haridass, Chandran (1990) The electronic band systems of ¹²C¹⁶O⁺. Masters thesis, Memorial University of Newfoundland.

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Abstract

The electronic band spectrum of the molecular ion ¹²C¹⁶O⁺ is of considerable importance to astrophysics as this species is one of the major constituent of the solar chromosphere, stellar atmospheres, and comet tails. It has also application in the study of radiative heating of hypersonic space craft at escape velocity and in the atmospheric fringe of the planet Venus. -- The molecular ion C0⁺ was excited in a hollow-cathode discharge tube of special design (S. P. Reddy and C. V. V. Prasad, J. Phys. E. Sci. Instrum. 22, 306 (1989)). The comet-tail (A²πi - X²∑⁺) band system of this molecular ion occurring in the cathode glow of the discharge tube was photographed in the spectral region 3345 - 8500 Å on a 2 m Bausch and Lomb dual-grating spectrograph in the first order of a 600 grooves/mm grating under medium resolution. Spectra were also recorded under high resolution on the same spectrograph in the second and third orders of a 1200 grooves/mm grating as well as on a 3.4 m Jarrell-Ash Ebert grating spectrograph in the second, third, and fourth orders of a 1200 grooves/mm grating. Of the seventeen bands with v' = 0 to 8 and v" = 0 to 4 recorded in this system, detailed rotational analysis of twelve (6-0, 4-0, 3-0, 2-0, 1-0, 2-1, 1-1, 0-1, 2-3, 0-2, 0-3, and 0-4) bands have been carried out. Rotational constants were obtained for the A²πi and X²∑⁺ states using the effective Hamiltonian proposed by Brown and his co-workers (J. M. Brown et al., J. Mol. Spectrosc. 74, 294 (1979)). -- Experimental data on the rotational structure of the first negative (B²∑⁺ - X²∑⁺) system (Rao, Astrophys. J. 111, 50 (1950) and Misra et al., J. Mol. Spectrosc. 125, 54 (1987)), the Baldet-Johnson (B²∑⁺ - A²πi) system (Jakubek et al., Can. J. Phys. 65, 94 (1987)), and the microwave spectrum of the v = 0 level (Sastry et al., Astrophys. J. 250, L91 (1981)) and of the v = 0, 1, and 2 levels (Bogey et al., J. Chem. Phys. 79, 4704 (1983)) of CO⁺ have been reanalysed using the effective Hamiltonian. A single set of molecular constants were then obtained for the X, A, and B states of CO⁺ by the method of a global fit of the molecular constants obtained from the analysis of the comet-tail, Baldet-Johnson and first negative systems and the microwave data. The vibrational constants for these three states were obtained from the band origin data.

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