Rotational Temperature Modeling of the Swan $\Delta \nu =0$ Band Sequence in Comet 122P/de~Vico

Abstract

We modeled observations of the C${}_2$ ${\mathrm{d}}^3{\Pi }_g-{\mathrm{a}}^3{\Pi }_u$ (Swan) $\Delta \nu =0$ sequence observed in spectra of comet 122P/de Vico obtained with the 2.7m Harlan J. Smith Telescope and Tull Coude spectrograph of McDonald observatory on 10/03/1995 and 10/04/1995. The data used spanned 4986-5169Åat R=$\lambda /\Delta \lambda$=60,000. We used the PGOPHER molecular spectra model to generate and fit synthetic spectra with the d${}^3{\Pi }_g$ having one and two rotational temperatures. We found the excited state had a two component rotational temperature, similar to that found for comet Halley. The modeled spectrum was sufficiently high quality that local perturbations were important to include. The large perturbation, b${}^3{\Sigma }_g^{-}(\nu =10)$, was added to our fits and some new estimates on its molecular constants were found.

This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Journal of Physical Chemistry, Part A:Isolated Molecules, Clusters, Radicals, and Ions; Environmental Chemistry, Geochemistry, and Astrochemistry; New Tools and Methods, copyright American Chemical Society after peer review