Heidelberg 1999 – scientific programme

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MO: Molekülphysik

MO 13: Chemische Reaktionen

MO 13.5: Talk

Friday, March 19, 1999, 15:00–15:15, PA1

Rotational Alignments of KBr of K+HBr/DBr in 0.1≤E_rel≤0.25-3.0 eV — •Victor Wei-Keh WU — Victor Basic Research Laboratory e.V., Bielefeld, Germany (http://www.uni-bielefeld.de/∼fkure)

The results from detailed QCT calculations for both reactions comparing available experimental data within 0.1≤E_rel≤0.25 eV show that the phenomenon and degree of alignment in K+HBr/DBr are almost the same. Approximations of ℓ(K+HBr)≈j′(KBr) and ℓ(K+DBr)≈j′(KBr) are well acceptable. Comparing with the CPOAM (Constrained Product Orbital Angular Momentum) model, which is approximated for the type of H₁+H₂L→H₁H₂+L, ⟨p₂(j′·k)⟩=-0.5+Z_m²(-lnZ_m+1/3), where Z_m=ℓ′/ℓ_max, our values of alignment p₂(j′·k)=(3cos²ϑ-1)/2 from QCT calculation show: both K+HBr and K+DBr are well suitable to be described with such approx.; K+HBr shows more suitable than K+DBr. The discrepancies between values of CPOAM and QCT are (CPOAM-p₂)/p₂=-1% for 0.4≤E_rel≤0.15 and -2% for 0.1≤E_rel≤0.075. Being nearly identical to the ideal value -0.5 of alignment, their absolute values are identical to the 3rd decimal position (-0.499∼-0.488). The lower E_rel is, the little greater discrepancy is from the ideal value; DBr causes more discrepancy than HBr. It can be therefore predicted that TBr will cause more. Such effect of discrepancy caused by heavier atom in diatomic molecule reactant is not as significant as by heavier one-atomic reactant (comparing with Ba+HBr). ℓ and ⟨ j′(KBr)⟩ from K+HBr/K+DBr are located within 2.05- 0.97/3.17-1.66 and 170.13-64.20/165.14-64.20 in unit ℏ respectively. The reaction products of K+HBr/DBr are scattered forwards at ⟨ω⟩=62.3-74.8^o. Ref. Victor W.-K. Wu et al., Verh.DPG. 2, 154 (1998)