Journal of Physical Chemistry A, Vol.113, No.40, 10641-10647, 2009
Correlation between the Atomic Alignment and the Alignment of XeX* (B, C) Rotation in the Reactions of Oriented Xe (P-3(2), M-J=2) + Halogen (X)-Containing Molecules
The polarization of the XeX* (B) and XeX* (C) emissions in the reactions of oriented Xe* (P-3(2), M-J = 2) + halogen (X)-containing molecules (CCl4, CF3Br, CF3I, CH3I, NF3) has been measured as a function of each magnetic M-J' substate in the collision frame. The parallel polarization of the XeX* (13, Q emissions to the relative velocity vector is commonly observed for all magnetic M-J' substates. The correlation between the atomic alignment (M-J') and the M-J'-dependent alignment (A(MJ')) of the XeX* (B, C) rotation is found to be extremely different between the XeX* (B) and XeX* (C) channels: For XeX* (B), A(MJ)' is highest for the M-J' = 0 state, except CCl4, whereas the vertical bar M-J'vertical bar = 2 states give the highest A(MJ') for XeX* (Q. Alternatively, the correlation between the configuration (L-Z') of the inner 5p orbital and the L-Z'-dependent alignment (All) of the XeX* (B, Q rotations is revealed. The collision with vertical bar L-Z'vertical bar = I causes a similar positive alignment A(LZ') for the XeX* (B) and XeX* (C) channels. The alignment A(LZ') at the collision with vertical bar L-Z'vertical bar = 0 is extremely different between the XeX* (B) and XeX* (C) channels. The collision with L-Z' = 0 induces no alignment of XeX* (C) except CF3I, that is, A(LZ'=0) approximate to 0, whereas it induces the higher positive A(LZ') of XeX* (B). The different M-J' dependence on the alignment of the XeX* (B, Q rotation between the XeX* (B) and XeX* (C) channels can be recognized as the change of reaction mechanism due to the difference in the favorable impact parameter for each M-J' state between the XeX* (B) and XeX* (C) channels, which reflects the Omega' conservation in the course of ion-pair (Xe+-RX-) formation.