Abstract book - Prof. Per Jensen, Ph.D. - Bergische Universität ...

140 Poster session, H27Submillimetre-wave spectroscopy of unstable imines of astrophysicalinterest: CH 2 NH and CH 2 CNHClaudio Degli Esposti 1 , Luca Dore 1 , Luca Bizzocchi 21 Dipartimento di Chimica “G. Ciamician”, Università di Bologna,Italy,[claudio.degliesposti , luca.dore]@unibo.it; 2 Centro de Astronomia e Astrofisica,Observaório Astronómico de Lisboa, Portugal, bizzocchi@oal.ul.ptDegli EspostiDore L.Bizzocchi L.Methanimine (CH 2 NH) and ketenimine (CH 2 CNH) are unstable molecules which havebeen detected in different astronomical sources 1,2 . Presently, the published rotationaldata for these species 3,4 are limited to frequency regions which are well below thespectral ranges covered by Herschel/HIFI and the ALMA bands 9 and 10. We haveextended the recordings of rotational lines of CH 2 NH and CH 2 CNH into thesubmillimetre-wave region, in order to improve the precision of ground-state rotationaland centrifugal distortion constants and make it possible to build a list of very accuraterest-frequencies for astrophysical purposes in the THz region (1σ uncertainties lowerthan 0.01 kms −1 in radial equivalent velocity).The investigation was carried out using a source-modulation microwave spectrometerbased on Gunn oscillators equipped with various frequency multipliers. The free-spacecell of the spectrometer was coupled to a high temperature reactor which allowed for theproduction of these species by gas-phase pyrolysis of 1,2 diaminoethane (for CH 2 NH),or isoxazole (for CH 2 CNH). The spectra were recorded in the frequency range 80–630GHz, and many tens of new ground-state transition frequencies were accuratelymeasured for each species. The hyperfine structure due to the 14 N nucleus was veryoften detected, and it was accounted for in the analysis.The complete sets of quartic and sextic centrifugal distortion constants could beaccurately determined for CH 2 NH, while less satisfactory results were obtained forCH 2 CNH, whose ground-state rotational spectrum is perturbed by a centrifugalresonance 5 . Further analyses are currently in progress to achieve a better modeling ofthe observed perturbation.References[1] P. D. Godfrey, R. D. Brown, B. J. Robinson, M. W. Sinclair, Astrophys. Lett., 113,119, 1973[2] F. J. Lovas, J. M. Hollis, A. J. Remijan, P. R. Jewell, ApJ, 645, L137, 2006[3] L. Dore, L. Bizzocchi, C. Degli Esposti, J. Gauss, J. Mol. Spectrosc., 263, 44, 2010[4] M. Rodler, R. D. Brown, P. D. Godfrey, L. M. Tack, Chem. Phys. Lett., 110, 447,1984[5] M. K. Bane, E. G., Robertson, C. D. Thompson, et al., J. Chem. Phys., 134, 234306,2011