Fourier Transform Emission Spectroscopy of the G 3  -X 3 , C 3  -X 3  and G 3  -C 3  systems of CoCl R. S. Ram Department of Chemistry, University of Arizona, Tucson, AZ I. Gordon, T. Hirao, S. Yu, P. F. Bernath Department of Chemistry, University of Waterloo, Waterloo, Ont. Canada N2L 3G1 B. Pinchemel Laboratoire PhLAM, Centre d’Etudes et de Recherches Lasers et Applications, Université des Science et Technologies de Lille, Villeneuve d’Ascq Cedex, France

Introduction Previous work on CoH, CoF and CoCl: CoH:M. Frendorf, C. M. Marian and B. A. Hess, JCP 99, 1215 (1993). [theoretical predictions for states below 2 eV., ground state: X 3 Φ i ] S. P. Beaton et al. JMS 164, 395 (1994). M. Barnes, A. Merer & G. F. Metha, JMS 164, 395 (1995). R. S. Ram, P. F. Bernath & S. P. Davis, JMS 175, 1 (1995). I. Gordon, R.J. Le Roy and P. F. Bernath, JMS 237, 11 (2006). [ground state: X 3 Φ i plus several low-lying states] CoF:A. G. Adam et al. CPL 230, 82 (1994). X. Zhang et al., JMS 220, 209 (2003). R. S. Ram, P. F. Bernath & S. P. Davis, JMS 173, 158 (1995). R. S. Ram, P. F. Bernath & S. P. Davis, JCP 104, 6949 (1996). T. Okabayashi and M. Tanimoto, JMS 221, 149 (2003). [X 3 Φ i, ground state and C 3 Δ, D 3 Δ and G 3 Φ low-lying states]

CoCl:P. Mesnage, C. R. Acad. Sci. 201, 389 (1935). K. P. More, Phys. Rev. 54, 122 (1938). V. G. Krishnamurthy, Ind. J. Phys. 26, 177 (1952). ( 0 + ground state?) A. J. Bridgeman, J. Chem. Soc. Daton Trans. 4765, (1997). (theoretical prediction: 3 Σ - ground state) A. G. Adam et al., JMS 212, 111 (2002). T. Hirao, B. Pinchemel and P. F. Bernath, JMS (2003). A. L. Wong, W. S. Tam and A. S. –C. Cheung, JCP 119, 3234 (2003). M. A. Flory, D. T. Halfen and L. M. Ziurys, JCP (2004). (Ground state is a 3 Φ state) Present work Observation of the G 3 Φ-X 3 Φ, C 3 Δ-X 3 Φ and G 3 Φ-C 3 Δ transitions of CoCl in the cm -1 region using a Fourier transform spectrometer.

Predicted states, Frendorf et al. JCP 99, 1215 (1993)

Observed low-lying states of CoCl, CoF and CoH ? ?

Experimental Observations Reaction of Co metal vapor and a small amount of HCl in a carbon tube furnace (King furnace). Bruker IFS 120 HR Fourier transform spectrometer at the University of Waterloo. Beamsplitter: visible quartz Detectors: Si photodiode He pressure: 150 TorrFurnace Temp.: ~2500ºC Scans: Resolution: 0.05 cm -1

Observations for CoCl G 3 Φ 3 –X 3 Φ 3 ( cm -1 )0-2, 0-1, 0-0, 1-0, 2-0, 3-0, 4-0 G 3 Φ 4 –X 3 Φ 4 ( cm -1 )0-2, 0-1, 0-0, 1-0, 2-0, 3-0, 4-0 C 3 Δ 2 -X 3 Φ 3 ( cm -1 )0-0 C 3 Δ 3 -X 3 Φ 4 ( cm -1 )0-0, 1-0, 2-0 G 3 Φ 3 - C 3 Δ 2 ( cm -1 ) 0-0 G 3 Φ 4 - C 3 Δ 3 ( cm -1 ) 0-0 Bands involving the X 3 Φ 2 spin component were not identified.

An overview of the 1-micron transition of CoCl

A portion of the 1-0 band near the R heads

An expanded portion of the G 3 Φ 3 -X 3 Φ 3, 1-0 band

A portion of the C 3 Δ-X 3 Φ, 0-0 band near the R heads

An expanded portion of the G 3 Φ 4 -C 3 Δ 3, 0-0 band

Constants (in cm -1 ) for the observed states of CoCl

Summary The G 3 Φ -X 3 Φ, C 3 Δ -X 3 Φ and G 3 Φ-C 3 Δ systems of CoCl have been observed at high resolution using a Fourier transform spectrometer. Molecules were excited in a high temperature carbon furnace. A rotational analysis of a number of bands has been obtained and the spectroscopic constants have been determined for the low-lying electronic states. The observation of the G 3 Φ and C 3 Δ states is consistent with the observations available for the CoF and CoH as well as theoretical predictions of Frendorf et al. (1993) for CoH.

NASA laboratory astrophysics program Natural Sciences and Engineering Research Council of Canada Acknowledgments