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Title: A COMPLETE SPECTROSCOPIC CHARACTERIZATION OF SO AND ITS ISOTOPOLOGUES UP TO THE TERAHERTZ DOMAIN

In order to obtain accurate terahertz center frequencies for SO and its isotopologues, we have studied the absorption spectrum of SO, {sup 34}SO, and {sup 33}SO up to 2.5 THz using continuous-wave terahertz photomixing based on a frequency comb providing an accuracy down to 10 kHz. Sulfur monoxide was produced in a radio frequency discharge of air in a cell containing pure sulfur. Together with the strong absorption signal of the main isotopologue, transitions of {sup 34}SO ({sup 34}S: 4.21%) and {sup 33}SO ({sup 33}S: 0.75%) were observed in natural abundance. The newly observed transitions constitute an extension of the observed rotational quantum numbers of the molecule toward higher N values, allowing an improvement of the molecular parameters for the three species. An isotopically invariant fit has been performed based on pure rotational and ro-vibrational transitions of all SO isotopologues, enabling their accurate line position prediction at higher frequencies. Thanks to this new set of parameters, it is now possible to predict with very high accuracy the frequencies of the ro-vibrational lines. This should enable the research of SO in the mid-IR using ground-based IR telescopes, space-based telescope archives (Infrared Space Observatory, Spitzer), and future space missions such as themore » James Webb Space Telescope. This set of parameters is particularly well adapted for the detection of SO lines in O-rich evolved stars or in molecular clouds in absorption against bright IR sources.« less
Authors:
; ; ;  [1] ;  [2]
  1. Laboratoire de Physico-Chimie de l'Atmosphère, EA 4493, Université du Littoral-Côte d'Opale, F-59140 Dunkerque (France)
  2. Group Molecular Astrophysics, ICMM, CSIC, C/Sor Juana Inés de la Cruz, N3, E-28049 Cantoblanco, Madrid (Spain)
Publication Date:
OSTI Identifier:
22364403
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 799; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ABSORPTION SPECTRA; KHZ RANGE; MOLECULES; QUANTUM NUMBERS; RADIOWAVE RADIATION; SPACE; STARS; SULFUR 33; SULFUR 34; SULFUR OXIDES; TELESCOPES