Rotational-energy transfer in ortho-para conversion of molecularly chemisorbed H on Pd(210)

植田 寛和   ; 福谷 克之

Ueta, Hirokazu; Fukutani, Katsuyuki

Clarifying energy transfer processes in molecular adsorption on solid surface is essential to understand gas/surface interaction. However, the rotational-energy transfer at surface remains less clear. The interconversion between ortho and para sates of H is accompanied by the nuclear spin flip and the rotational-energy transfer. We study the ortho-to-para (o-p) conversion of molecularly chemisorbed H on Pd(210) using a combination of a pulsed molecular beam, photo-stimulated desorption, and resonance-enhanced multiphoton ionization technique. In the present contribution, we present the surface temperature (TS) dependence of the o-p conversion rate in the temperature range of 40-60 K. It is found that the conversion rate accelerates with increasing TS. Based on the results obtained, the analysis of the rotational-energy of adsorbed H and the proposed rotational-energy transfer paths, we discuss the rotational-energy transfer process.