The A~3sum~--X~3sum~- electronic transition of HC_6N

摘要

A combined matrix and gas phase study is presented to identify the A~3 #SIGMA#~- -X~3#SIGMA#~- electronic tramsflAon ot tYse linear ‘triplex isomer ot YXC6~M and isotopic ilerivalive DC6N. Absorpfion spectra have been observed in a 6 K neon matrix after mass selective deposition and in the gas phase by cavity ring down spectroscopy through a supersonic planar plasma. The band origin of the O_0~0 A~3#SIGMA#~- -X~3#SIGMA#~-electronic transition of HC6N is determined to be at 21 208.60(5) cm~(-1), shifted-30cm~(-1) to the blue of the neon matrix value. Rotational analysis indicates that the chain is slightly stretched on electronic excitation, yielding B,0.027 92(5) cm~(-1). Transitions to vibrationally excited levels in the upper A~3 #SIGMA#~-state are observed as well. The results are compared with a rotationally resolved spectrum of the O_0~0 A~3#SIGMA#_u~--X~3#SIGMA#_g~- electronic transition of theg isoelectronic HC_7H species.