Generation and characterization of highly vibrationally excited molecular beam

Abstract

A simple method to generate and characterize a pure highly vibrationally excited azulene molecular beam is demonstrated. Azulene molecules initially excited to the S4 state by 266-nm UV photons reach high vibrationally excited levels of the ground electronic state upon rapid internal conversion from the S4 electronically excited state. VUV laser beams at 157 and 118 nm, respectively, are used to characterize the relative concentrations of the highly vibrationally excited azulene and the rotationally and vibrationally cooled azulene in the molecular beam. With a laser intensity of 34 mJ/cm2, 75% of azulene molecules absorb a single 266-nm photon and become highly vibrationally excited molecules. The remaining ground-state azulene molecules absorb two or more UV photons, ending up either as molecular cations, which are repelled out of the beam by an electric field, or as dissociation fragments, which veer off the molecular-beam axis. No azulene without absorption of UV photons is left in the molecular beam. The molecular beam that contains only highly vibrationally excited molecules and carrier gas is useful in various experiments related to the studies of highly vibrationally excited molecules.

Energy transfer of highly vibrationally excited naphthalene. II. Vibrational energy dependence and isotope and mass effects

“…[33][34][35][36][37]42,43 Only a brief description is described here. [33][34][35][36][37]42,43 Only a brief description is described here.…”

“…Some experimental results are available for comparison with the calculations. [34][35][36][37][38] The advantages of the crossed-beam experiments are that collisions are controlled to occur under a specific initial conditions, i.e., under single collision conditions at a given collision energy and at very low rotational temperature ͑Ͻ2 K͒. [27][28][29][30][31][32] The vibration energy relaxation of azulene by He, Ne, Ar, Kr, and Xe in a thermal system showed the mass effects, the average energy transfer of which increases from He, Ne, and Ar to Kr but levels off from Kr to Xe.…”