Hannover 2003 – wissenschaftliches Programm
MO 6.24: Poster
Dienstag, 25. März 2003, 16:00–18:30, Lichthof
Direct Observation of the Steric Effect in Penning Ionisation Reaction of Oriented Ar*(3P2,0)+CHCl3→CHCℓ2++Cℓ+e−+Ar (II) — •Masanori YAMATO1, Seiki OKADA1, Victor Wei-Keh WU1,2,3, Hiroshi OHOYAMA1, and Toshio KASAI1 — 1Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan — 2Victor Basic Research Laboratory e.V., Gadderbaumer-Str. 22, D-33602 Bielefeld, Germany — 3Department of Electronic Engineering, Lan-Yang Institute of Technology, 261 Tou-Cheng, I-Lan, Taiwan, Republic of China
Steric effect in Penning ionization of oriented
CHCℓ3→CHCℓ2++Cℓ+e−+Ar has been directly observed at Erel = 0.13 eV. CHCℓ2+ ions were measured for H−end, CCℓ3−end and sideways orientations. The steric opacity function reveals that CCℓ3−end orientation is more favorable than H−end, and the sideways approach is to be more favorable than collinear approaches with both ends. There is good correlation betw. the Penning ionization anisotropy and electron density distr. of the 2a2 HOMO orbital of CHCℓ3 around the sideways, by ab initio calc. with QCISD level on the 6-31+G(d) basis sets of GAUSSIAN-98. Dynamical simulation is sofar impossible, because three bond lengths of CCℓ3 of CHCℓ3 are not differentiable during the reaction, even immediately before one Cℓ is released, and the involved PES cannot be reconstructed. Ref. J.C.P.113, 6673 (2000). Wu is deeply thankful for the full financial aids of JSPS in 1999−2000 (No.L99536), all the colleagues and friends, who have helped and taught him, and the kindly hospitality of Prof.Dr.Kasai.