Rotationally resolved spectra of the 4051Å comet band of C3 for all six 12C and 13C isotopologues

Lowest bending mode of 13C-substituted C3 and an experimentally derived structure

“…An absorption spectrum was obtained when tuning the THzfrequency in steps of 0.25 MHz over the entire spectral range, by taking the averaged 100 µs time-signals of 30 laser shots 19(32) 0.030 70(126) 0.021 78 (7) 0.022 90(62) q JJ × 10 6 11.5(11) q JJJ × 10 9 5.48(87) a Global fit including high resolution 12 C 3 data. 13,14,16,19 b Global fit including data from Krieg et al 19 and Haddad et al 21 c Global fit including optical data set. 21 d Global fit including data from Moazzen-Ahmadi and McKellar.…”

“…Moazzen-Ahmadi and McKellar 20 performed infrared measurements using 13 C-enriched precursors and derived molecular parameters for the isotopologues 12 C 12 C 13 C and 13 C 13 C 13 C. Later, Krieg et al 19 measured the first spectra of 12 C 13 C 12 C at 3 µm. Optical spectra of 13 C-isotopologues were reported by Haddad et al, 21 although with less frequency accuracy compared to the infrared studies. So far there have been no spectra published of the 13 C-substituted C 3 at the ν 2 lowest bending mode except Krieg et al 19 who reported a weak absorption band, centered at 60.747 cm 1 which was incorrectly assigned to singly substituted 12 C 12 C 13 C. Our present data give evidence that the 60.747 cm 1 absorption belongs to the ν 2 band of 13 C 13 C 12 C. Based on the faulty assignment, our search for interstellar 12 C 12 C 13 C using the Herschel space telescope failed, which finally led to the present systematic study on the low bending mode of C 3 and its 13 C-isotopologues.…”

“…These new data together with IR-data reported by Krieg et al 19 and optical data from Haddad et al 21 were analyzed in a weighted least squares fit to derive molecular parameters as given in Table II. We found excellent agreement with ab initio data of Schröder and Sebald; 22 in particular the measured and calculated line center positions agree within 6 GHz.…”

“…All measured line positions were determined very precisely with uncertainties of less than 100 kHz. Accurate line positions are given in Table III, and molecular parameters derived from a weighted global fit analysis including IR-data published by Krieg et al 19 and optical data by Haddad et al 21 can be found in Table II.…”

Division B Commission 14 Working Group: Molecular Data

“…Recent theoretical efforts on CN involved molecular properties of its low-lying electronic states (Shi et al 2011a) and the determination of photodissociation cross sections (El-Qadi & Stancil 2013). Two studies on C 3 appeared; one provides laboratory spectra on A-X bands for C 3 and its isotopologues (Haddad et al 2014) and the other gives oscillator strengths for a number of these bands based on astronomical measurements (Schmidt et al 2014).…”