Rotational spectra of the carbon chain free radicals C10H, C12H, C13H, and C14H

The four carbon chain radicals C10H, C12H, C13H, and C14H have been observed in a pulsed supersonic molecular beam with a Fourier transform microwave spectrometer. The radicals were produced in a discharge through a dilute diacetylene/neon mixture in the throat of a supersonic nozzle. All are linear with 2Π electronic ground states, and all except C14H have resolved lambda-type doubling. For each species at least ten rotational transitions, between 6 and 16 GHz, were measured in the lowest spin component, which is 2Π3/2 for C10H, C12H, and C14H, and 2Π1/2 for C13H. Only three spectroscopic constants in the standard Hamiltonian for a molecule in a 2Π state were required to reproduce the spectra to a few parts in 107: an effective rotational constant, a centrifugal distortion constant, and a lambda-type doubling constant. All of the chains here have abundances in the most intense part of the supersonic molecular beam of ⩾5×109 per gas pulse, which suggests that optical transitions of all four may be detecta...

[1]  R. Woods,et al.  The laboratory microwave spectrum of the cyanide radical in its X 2Σ+ ground state , 1999 .

[2]  H. Kohguchi,et al.  Laser-induced fluorescence spectroscopy of the C4H and C4D radicals in a supersonic jet , 1998 .

[3]  J. Grabow,et al.  Laboratory Detection of the Carbon Chains HC15N and HC17N , 1998 .

[4]  P. Thaddeus,et al.  Eight New Carbon Chain Molecules , 1997 .

[5]  H. Kohguchi,et al.  Laser-induced fluorescence spectroscopy of the C̃ 2Σ+−X̃ 2Π1/2 band system of jet-cooled CCN radical , 1997 .

[6]  M. Head‐Gordon,et al.  A COUPLED-CLUSTER AB INITIO STUDY OF TRIPLET C3H2 AND THE NEUTRAL-NEUTRAL REACTION TO INTERSTELLAR C3H , 1997 .

[7]  J. Maier,et al.  Electronic spectrum of C6H: 2Π-X2Π in the gas-phase detected by cavity ringdown , 1997 .

[8]  P. Kalmus,et al.  Microwave spectroscopy of the carbon chain radical C11H , 1997 .

[9]  P. Kalmus,et al.  Laboratory Detection of the C9H Radical , 1996 .

[10]  P. Thaddeus,et al.  Laboratory Detection of the C7H Radical , 1996 .

[11]  D. Woon.  A correlated ab initio study of linear carbon-chain radicals CnH (n = 2-7). , 1995, Chemical physics letters.

[12]  John P. Maier,et al.  Electronic absorption spectra of linear carbon chains in neon matrices. III. HC2n+1H , 1995 .

[13]  L. Adamowicz,et al.  Ab initio characterization of electronically excited states in highly unsaturated hydrocarbons , 1995 .

[14]  G. Mamon,et al.  The formation of cyanopolyyne molecules in IRC + 10216 , 1993 .

[15]  E. Hirota.  Microwave and Infrared Spectra of Free Radicals and Molecular Ions , 1992 .

[16]  S. S. Sidhu,et al.  The Homogeneous Pyrolysis of Acetylene II: The High Temperature Radical Chain Mechanism , 1992 .

[17]  A. D. McLean,et al.  Is interstellar detection of higher members of the linear radicals CnCH and CnN feasible? , 1991, The Astrophysical journal.

[18]  E. Colbourn,et al.  An effective Hamiltonian for diatomic molecules . Ab initio calculations of parameters of HCl , 1979 .

[19]  G. Herzberg,et al.  Molecular Spectra and Molecular Structure: I. Spectra of Diatomic Molecules , 1944 .