Rotational- and vibrational-state resolved HF-surface interactions investigated by surface light-induced drift

Abstract

Articles you may be interested inEfficient vibrational and translational excitations of a solid metal surface: State-to-state time-of-flight measurements of HCl ( v = 2 , J = 1 ) scattering from Au (111) Rotational and vibrational wave packet motion during the infrared multiphoton excitation of HF State-to-state unimolecular reaction dynamics of HOCl near the dissociation threshold: The role of vibrations, rotations, and IVR probed by time-and eigenstate-resolved spectroscopy Experiments using surface light-induced drift are performed to yield information on the rotational (J) and vibrational (v) state dependence of molecule-surface interactions. Data are presented for the change in accommodation coefficient for tangential momentum transfer ␣ upon excitation of HF interacting with a polycrystalline LiF surface ͑on a Cu substrate͒ and a hydrophobic stearic-acid monolayer ͑on a stainless-steel substrate͒. We employed both P-and R-branch excitation of HF in the fundamental vibrational band (vϭ0→1) with Jϭ0 -4, using a continuously tunable color-center laser (Ϸ2.5 m). By combining the results for the P-and R-branch, we find that the influences of J and v upon the molecule-surface interaction can be considered independent to a good approximation. It is found that ␣ decreases upon vibrational excitation vϭ0→1, whereas it increases with increasing J. The J and v dependences of ␣ are discussed in the framework of a unified kinetic theory of molecule-surface interaction.

Microscale Molecular Tennis

“…From the data it is found that a decreases slightly upon vibrational excitation (by almost 1 x 10~3 in the above case). This may be qualitatively explained by vibrational-to-translational energy transfer arguments [15]. By contrast, a is found to increase with increasing J for the case studied.…”

“…been shown [15] that the two contributions can often be separated into a rotational and a vibrational part: Aa = Aa roi + Aayi&. This is achieved by combining the results for P( J) and R( J -1) transitions.…”

Surface light-induced drift due to anisotropic gas-surface scattering in models with and without boundary conditions

“…With R ∼ 1 mm, this yields L/R ∼ 10 3 amplification factor in (1). Thus, even a small change in the value of α upon excitation can produce a significant pressure drop in the cell, which has been demonstrated in the experiments on SLID [20][21][22][23][24]. The change in the magnitude of the accommodation coefficient often turns out to be quite low indeed (about 0.1% for vibrotational transitions of 13 CH 3 F and OCS on quartz and 1.4% for 13 CH 3 F on LiF(100) [20][21][22][23]).…”