15min:

KENSUKE HARADA, AKIHITO OKUMURA, TAKEHIKO TANAKA AND KEIICHI TANAKA, Department of Chemistry, Faculty of Sciences, Kyushu University, Hakozaki, Higashiku, Fukuoka, 812-8581 JAPAN.

The Ne-HCN cluster is a weakly bound complex with the binding energy (D₀) of 39 cm^-1. In the present work, we have observed the vdW bending bands of Ne-HCN. A pulsed jet millimeter-wave spectrometer was used for the experiment. The millimeter wave radiation passed twenty times through the jet expansion using a White type optical path to attain high sensitivity. The 14 and 22 vdW transitions were observed for the ₁- ₀ and ₁- ₀ bands in the frequency region of 79-201 GHz. Most lines were split into the hyperfine components of nitrogen nucleus. From the eQq constants, the root mean square amplitudes \langle ² \rangle^1/2 of the HCN part were estimated to be 47^o, 56^o, and 63^o for the ₀, ₁, and ₁ states. The center of mass distance of the intermolecular bond were derived from the rotational constants to be 3.89, 3.85, and 3.66 Å for those states.