Interatomic potential parameters of CdHe van der Waals complex derived from excitation spectrum of the C 11(5 1P 1) ← X 10 +(5 1S 0) vibrational transition
Abstract
The first time observed excitation spectrum of the C 11(5 1P 1) ← X 10 +(5 1S 0) transition in CdHe van der Waals molecules is reported. Vibrational spectrum in the UV region (2286.0-2296 Å) was excited in a continuous molecular-jet-expansion beam of CdHe seeded in helium using an in-house-built nitrogen-dye laser system. The excitation spectrum exhibits two vibrational components (v←v=0) highly broadened by means of unresolved rotational structure and some additional contributions of "hot-bands" componenets (v←v=1). The last effect is due to an extremely small separation of the vibrational levels in the ground X 10 + state of the CdHe molecule, where v=0 vibrational level is separated from v=0 by merely 6.0 cm -1. It follows therefore that even in an extremely cold environment ( Tv ≈ 10 K) of a jet-expansion beam the population of v=1 level is feasible, due to some residual collisions, and hence the v←v=1 transitions are highly probable. The assignment of vibrational bands and numerical analysis of the spectrum was based and obtained with the aid of a rigorous computer simulation of the C 11 ← X 10 + transition including the impact of rotational structure and hot-bands contributions. As a result we obtained optical potential parameters of the C 11(5 1P 1) state of CdHe molecule which are further discussed in terms of our recent (and only existing) experimental results regarding the X 10 +, B1(5 3P 1) and A0 +(5 3P 1) states of CdHe as well as in terms of ab initio calculations results.
- Publication:
-
Spectrochimica Acta Part A: Molecular Spectroscopy
- Pub Date:
- July 2007
- DOI:
- 10.1016/j.saa.2006.08.025
- Bibcode:
- 2007AcSpA..67..730C