Bonn 2000 – wissenschaftliches Programm

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MO: Molekülphysik

MO 14: Poster I: Reaktive Stöße

MO 14.3: Poster

Mittwoch, 5. April 2000, 10:30–13:00, Aula

Intracluster Reaction of HBr·N₂O→OH(A²Σ)+N₂(X¹Σ)+Br — •Victor Wei-Keh WU, Hiroshi OHOYAMA, and Toshio KASAI — Graduate School of Science, Osaka Univ., J-560-0043 Toyonaka, Japan

The reaction mechanism of HBr·N₂O(X¹Σ⁺)→OH(A²Σ)+N₂(X¹Σ _g⁺)+Br has been deduced from the calculated results of H+N₂O(X¹Σ⁺)→OH(A²Σ)+N₂(X¹Σ_g⁺). The calculated two trends running into products OH with high (3048 K) and low (409 K) mean T_rot match well the experimental results of N_v′=1(b)/N_v′=0(b) ≈ 0.75 for T_rot≈750 K, and N_v′=1(b)/N_v′=0(b) ≈ 0.45±0.15 for T_rot≈3500 K. For the cases b is slightly larger, the product OH will be easily higher rotationally excited (high T_rot) because of migration of H, where H approaches first N₂ instead of O. Before H leaves N₂, H will migrates to O, be attracted by O and rotate around it. During the intracluster reaction of HBr·N₂O, H of HBr may approach first closer to N₂, then migrate to O and OH is formed. The affinities between H and N, Br and O (H and O, Br and N) are almost equal, may increase the possibility of migration (Elektronegativities of Br, H, N and O are 2.85, 2.20, 3.05 and 3.50, respectvely.). This kind of reaction prefers larger b (≥ 0.55 Å). The rotational process during the transformation is significant in the plot of atompair distance - reaction time. Such phenomenon must be more significantly in HBr·N₂O with participation of Br. This is a typical case that product will be highly rotationally instead of vibrationally excited after migration. ⋆Wu is from Victor Basic Research Laboratory e.V., Bielefeld, Germany, with 100% financial aids of JSPS in 1999-2000 (No.L99536).