Vibrationally Hot Bands of the SiCN Ã 2Δ – X̃ 2Π System
journal contributionposted on 03.10.2013, 00:00 by Masaru Fukushima, Takashi Ishiwata
We have generated SiCN in supersonic free jet expansions and observed the laser induced fluorescence (LIF) spectrum. In addition to the vibronic bands from the vibrationless level of the X̃ 2Π state, the hot bands from the bending vibrational level, Ã (0110) 2Φ – X̃ (0110) 2Δ and Ã (0110) 2Π – X̃ (0110) 2Σ(−), have been measured. The rotational energy levels were reasonably analyzed as those of the 2K′ – 2K″ transitions, but their line intensities calculated from the Hönl–London factors derived in the intermediate case between Hund’s case (a) and (b) could not reproduce the observed spectra. The Hönl–London factors derived in the 2Λ′ – 2Λ″ (2Δ – 2Π) transition reasonably reproduced the spectra. It indicates that coupling between the electronic orbital and vibrational angular momenta is weak in the SiCN 2Δ – 2Π system, and a basis set of |Λ v2 l Σ;J P MJ⟩, the so-called “l-basis”, better describes the system than that of |Λ v2 K Σ;J P MJ⟩.