Initial dissolution of D2O at the gas-liquid interface of the ionic liquid [C4min][NTf2] associated with hydrogen-bond network formation.

We have studied the initial dissolution of D2O at the interfacial surface of the flowing jet sheet beam of the ionic liquid (IL) [C4min][NTf2] using the King and Wells method as a function of both the temperature and collision energy of the IL. The initial dissolution probability of D2O into the IL [C4min][NTf2] was found to follow the general propensity that the solubility of gases into a liquid decreases with temperature. However, a large partial molar enthalpy and entropy for the initial dissolution of D2O in the IL [C4min][NTf2] were observed from the temperature dependence of the initial dissolution probability: ΔHl = -53 ± 8 kJ mol-1, ΔSl = -210 ± 30 J mol-1 K-1. In addition, it was found that the collision energy significantly reduced the initial dissolution probability. We propose that the associated D2O molecules at the interface of the IL [C4min][NTf2] make a hydrogen-bond network around the [NTf2]- anion before dissolution into the deeper portion of the interface layer.

Atomic alignment effect on reactivity and on product alignment in the energy-transfer reaction of oriented Ar (3P2, 4s [3/2]2, M(J) = 2) + Kr (4p6, 1S0) → Ar (3p6, 1S0) + Kr (5p [3/2]2).

Steric effect for the formation of Kr (5p [3/2]2) in the energy transfer reaction of Ar (³P2, 4s [3/2]2) + Kr has been studied by using an oriented Ar (³P2, 4s [3/2]2, M(J) = 2) beam at a collision energy of ∼0.09 eV. The emission intensity of Kr (5p [3/2]2) is ca. 2 times enhanced when the angular momentum (J(Ar)) of Ar (³P2) is aligned perpendicular to the relative velocity vector (v(R)). In addition, the Kr (5p [3/2]2) emission is highly polarized parallel to v(R) (I(∥)/I(⊥) ∼ 1.2) when JAr is aligned perpendicular to v(R). The observed polarization moments indicate that the alignment of the unpaired Ar (3p) orbital of Ar (³P2) to v(R), (Σ (|L'| = 0), Π (|L'| = 1)), dominates the energy transfer probability (σ(Π)(∥): σ(Σ)(∥): σ(Π)(⊥): σ(Σ)(⊥) = 0.49:1.33:0.55:1.23) and also the alignment of the Kr (5p) orbital of Kr (5p [3/2]2) to v(R): the Σ-configuration of the Ar (3p) orbital leads to the parallel alignment (Σ-configuration) of the Kr(5p) orbital to v(R), conversely, the Π-configuration of Ar (3p) orbital leads to the perpendicular alignment (Π-configuration) of the Kr(5p) orbital. In addition, the selectivity of the alignment of the Kr (5p) orbital turns out to vary from perpendicular to parallel as the collision energy increases after a threshold down to 0.03 eV.

Collision energy dependent cross section and rotational alignment of NO (A 2Σ+) in the energy-transfer reaction of N2 (A 3Σu+) + NO (X 2Π) → N2 (X 1Σg+) + NO (A 2Σ+).

We have studied the collision energy dependent cross section and alignment of NO (A (2)Σ(+)) rotation in the energy-transfer reaction of N2 (A (3)Σ(u)(+)) + NO (X (2)Π) → N2 (X (1)Σ(g)(+)) + NO (A (2)Σ(+)) at the collision energy (E) region of 0.03-0.2 eV. NO (A (2)Σ(+)) emission in two linear polarization directions in the collision frame (parallel (∥) and perpendicular (⊥) with respect to the relative velocity vector (vR)) has been measured as a function of collision energy. NO (A (2)Σ(+)) rotation (J-vector) turns out to be aligned perpendicular to vR. In addition, collision energy is found to enhance the degree of alignment of NO (A (2)Σ(+)) rotation. The collision energy dependent cross sections σ(∥,(⊥))(E) (excitation functions) show a rapid fall-off following an initial rise with a threshold less than 0.02 eV. The excitation function at the parallel alignment of NO (A (2)Σ(+)) rotation, σ(J∥v(R), (E), is slightly shifted to the low collision energy region as compared with σ(J ⊥ vR, E). We propose that the rapid fall-off feature in the excitation function is attributed to the multidimensional nonadiabatic transitions.

Vector correlation between the alignment of reactant N2 (A 3Σu+) and the alignment of product NO (A 2Σ+) rotation in the energy transfer reaction of aligned N2 (A 3Σu+) + NO (X 2Π) → NO (A 2Σ+) + N2 (X 1Σg+).

The vector correlation between the alignment of reactant N2 (A (3)Σu(+)) and the alignment of product NO (A (2)Σ(+)) rotation has been studied in the energy transfer reaction of aligned N2 (A (3)Σu(+)) + NO (X (2)Π) → NO (A (2)Σ(+)) + N2 (X (1)Σg(+)) under the crossed beam condition at a collision energy of ~0.07 eV. NO (A (2)Σ(+)) emission in the two linear polarization directions (i.e., parallel and perpendicular with respect to the relative velocity vector v(R)) has been measured as a function of the alignment of N2 (A (3)Σu(+)) along its molecular axis in the collision frame. The degree of polarization of NO (A (2)Σ(+)) emission is found to depend on the alignment angle (θ(v(R))) of N2 (A (3)Σu(+)) in the collision frame. The shape of the steric opacity function at the two polarization conditions turns out to be extremely different from each other: The steric opacity function at the parallel polarization condition is more favorable for the oblique configuration of N2 (A (3)Σu(+)) at an alignment angle of θ(v(R)) ~ 45° as compared with that at the perpendicular polarization condition. The alignment of N2 (A (3)Σu(+)) is found to give a significant effect on the alignment of NO (A (2)Σ(+)) rotation in the collision frame: The N2 (A (3)Σu(+)) configuration at an oblique alignment angle θ(v(R)) ~ 45° leads to a parallel alignment of NO (A (2)Σ(+)) rotation (J-vector) with respect to v(R), while the axial and sideways configurations of N2 (A (3)Σu(+)) lead to a perpendicular alignment of NO (A (2)Σ(+)) rotation with respect to vR. These stereocorrelated alignments of the product rotation have a good correlation with the stereocorrelated reactivity observed in the multi-dimensional steric opacity function [H. Ohoyama and S. Maruyama, J. Chem. Phys. 137, 064311 (2012)].

Stereo correlated dynamics in the energy transfer process of aligned N2 (A 3Σ(u)+) + oriented NO (X 2Π, Ω = 1∕2) → NO (A 2Σ+) + N2 (X 1Σ(g)+).

Steric effect for the NO (A (2)Σ(+)) formation in the aligned N(2) (A (3)Σ(u)(+)) + oriented NO (X (2)Π, Ω = 1∕2) reaction has been observed as a function of the mutual orientational configurations between the two molecular reactants in the collision frame. Multidimensional molecular steric opacity function has been determined. A significant NO (X (2)Π) alignment dependence is recognized in contrast with little dependence on NO (X (2)Π) orientation. The NO alignment selectivity turns out to depend on the N(2) (A (3)Σ(u)(+)) alignment: The axial configuration of NO (X (2)Π) is favorable for the axial and sideways configurations of N(2) (A (3)Σ(u)(+)), while the sideways configuration of NO (X (2)Π) is favorable for the oblique configuration of N(2) (A (3)Σ(u)(+)) at an orientation angle of θ(v(R)) ∼ 45°. with respect to the relative velocity (v(R)).

Alignment effect of N2(A3Σu+) in the energy transfer reaction of aligned N2(A3Σu+) + NO(X2Π) → NO(A2Σ+) + N2(X1Σg+).

Steric effect in the energy transfer reaction of N(2)(A(3)Σ(u)(+)) + NO(X(2)Π) → NO(A(2)Σ(+)) + N(2)(X(1)Σ(g)(+)) has been studied under crossed beam conditions at a collision energy of ~0.07 eV by using an aligned N(2)(A(3)Σ(u)(+)) beam prepared by a magnetic hexapole. The emission intensity of NO(A(2)Σ(+)) has been measured as a function of the magnetic orientation field direction (i.e., alignment of N(2)(A(3)Σ(u)(+))) in the collision frame. A significant alignment effect on the energy transfer probability is observed. The shape of the steric opacity function turns out to be most reactive at the oblique configuration of N(2)(A(3)Σ(u)(+)) with an orientation angle of γ(v(R)) ~ 45° with respect to the relative velocity vector (v(R)), which has a good correlation with the spatial distribution of the 2pπ(g)* molecular orbital of N(2)(A(3)Σ(u)(+)). We propose the electron exchange mechanism in which the energy transfer probability is dominantly controlled by the orbital overlap between N(2)(2pπ(g)*) and NO(6σ).

Atomic alignment effect in the dissociative energy transfer reaction of metal carbonyls (Fe(CO)5, Ni(CO)4) with oriented Ar (3P2, M(J) = 2).

The atomic alignment effect has been studied for the dissociative energy transfer reaction of metal carbonyls (Fe(CO)(5), Ni(CO)(4)) with the oriented Ar ((3)P(2), M(J) = 2). The emission intensity from the excited metal products (Fe*, Ni*) has been measured as a function of the atomic alignment in the collision frame. The selectivity of the atomic orbital alignment of Ar ((3)P(2), M(J) = 2) (rank 2 moment, a(2)) is found to be opposite for the two reaction systems; the Fe(CO)(5) reaction is favorable at the Π configuration (positive a(2)), while the Ni(CO)(4) reaction is favorable at the Σ configuration (negative a(2)). Moreover, a significant spin alignment effect (rank 4 moment, a(4)) is recognized only in the Ni(CO)(4) reaction. The atomic alignment effect turns out to be essentially different between the two reaction systems; the Fe(CO)(5) reaction is controlled by the configuration of the half-filled 3p atomic orbital of Ar ((3)P(2)) in the collision frame (L dependence), whereas the Ni(CO)(4) reaction is controlled by the configuration of the total angular moment J (including spin) of Ar ((3)P(2)) in the collision frame (J dependence). As the origin of J dependence observed only in the Ni(CO)(4) reaction, the correlation (and/or the interference) between two electron exchange processes via the electron rearrangements is proposed.

Steric effect in the energy transfer reaction of oriented CO (a 3Π, v'=0, Ω=1 and 2) + NO (X 2Π) → NO (A 2Σ+, B 2Π) + CO (X 1Σ+).

The oriented CO (a (3)Π, v' = 0, Ω = 1 and 2) beam has been prepared by using an electric hexapole and applied to the energy transfer reaction of CO (a (3)Π, v' = 0, Ω = 1 and 2) + NO (X (2)Π) → NO (A (2)Σ(+), B (2)Π) + CO (X (1)Σ(+)). The emission spectra of NO (A (2)Σ(+), B(2)Π) have been measured at three orientation configurations (C-end, O-end, random). The shape of the emission spectra (and/or the internal excitation of products) turns out to be insensitive to the molecular orientation. The vibrational distributions of NO (A (2)Σ(+), v' = 0-2) and NO (B (2)Π, v' = 0-2) are determined to be N(v'=0):N(v'=1):N(v'=2) = 1:0.40 ± 0.05:0.10 ± 0.05 and N(v'=0):N(v'=1):N(v'= 2) = 1:0.6 ± 0.1:0.7 ± 0.1, respectively, and the branching ratio γ/ß [=NO (A (2)Σ(+))/NO (B (2)Π)] is estimated to be γ/ß âˆ¼ 0.3 ± 0.1 by means of spectral simulation. These vibrational distributions of NO (A, B) can be essentially attributed to the product-pair correlations between CO (X, v″) and NO (A (2)Σ(+), v' = 0-2), NO (B (2)Π, v' = 0-2) due to energetic restriction under the vibrational distribution of CO (X, v″) produced from the vertical transition of CO (a (3)Π, v' = 0) → CO (X, v″) in the course of energy transfer. The steric opacity function has been determined at two wavelength regions: 220 < λ < 290 nm [NO (A → X) is dominant]; 320 < λ < 400 nm [NO (B → X) is dominant]. For both channels NO (A (2)Σ(+), B(2)Π), a significant CO (a (3)Π) alignment effect is recognized; the largest reactivity at the sideways direction with the small reactivity at the molecular axis direction is observed. These CO (a (3)Π) alignment effects can be essentially attributed to the steric asymmetry on two sets of molecular orbital overlap, [CO (2π) + NO (6σ (2π))] and [CO (5σ) + NO (1π (2π))]. All experimental observations support the electron exchange mechanism that is operative through the formation of a weakly bound complex OCNO.

Collision-induced harpooning observed in the excimer formation in the oriented NF3 + oriented Kr*(3P2, MJ = 2) reaction.

We have studied how the KrF* formation in the NF3 þ Kr*(3P2) reaction depends on the mutual configuration between the orientation of the NF3 molecule and the alignment of the Kr*(3P2, M(J) = 2) atom in the collision frame. The molecular steric opacity function has been determined as a function of the atomic orbital alignment (M'(L)) in the collision frame. The molecular steric opacity function turns out to depend remarkably on M'(L) ; the |M'(L)| = 1 alignment is favorable at the molecular axis direction, whereas the M'(L) = 0 alignment is favorable at the sideways direction with a very poor reactivity at the molecular axis direction. The influence of deformation of the NF3 geometry on the electron affinity has been evaluated by ab initio calculation, and the M'(L) dependent intermolecular potential has been estimated from the interaction potential for the bromine-rare gas system. We propose the "collision-induced harpooning mechanism" as a novel process for the harpooning in which collisional deformation of the NF3 geometry with C(s) symmetry plays an important role as an initiating factor on electron transfer for the formation of NF3(-) due to increasing the electron affinity of NF3 and due to localizing the negative charge on the closest F-atom of NF3(-) anion. All experimental observations can support the collision-induced harpooning mechanism.

Rotationally correlated reactivity in the CH (v = 0, J, F(i)) + O2 → OH (A) + CO reaction.

The rotational-state-selected CH (v = 0, J, F(i)) beam has been prepared by using an electric hexapole and applied to the crossed beam reaction of CH (v = 0, J, F(i)) + O(2) → OH (A) + CO at different O(2) beam conditions. The rotational state selected reactive cross sections of CH (RSSRCS-CH) turn out to depend remarkably on the rotational state distribution of O(2) molecules at a collision energy of ∼ 0.19 eV. The reactivity of CH molecules in the N = 1 rotational states (namely ∣J = 1∕2, F(2)> and ∣J = 3∕2, F(1)> states, N designates the angular momentum excluding spin) becomes strongly enhanced upon a lowering of the rotational temperature of the O(2) beam. The RSSRCS-CH in these two rotational states correlate linearly with the population of O(2) molecule in the specific K(O(2)) frame rotation number states: CH(|J = 1/2,F(2)>) with O(2)(|K(O(2)) = 1>);CH(|J = 3/2,F(1)>) with O(2)(|K(O(2)) = 3>). These linear correlations mean that the rotational-state-selected CH molecules are selectively reactive upon the incoming O(2) molecules in a specific rotational state; here, we use the term "rotationally correlated reactivity" to such specific reactivity depending on the combination of the rotational states between two molecular reactants. In addition, the steric asymmetry in the oriented CH (∣J = 1∕2, F(2), M = 1∕2>) + O(2) (|K(O(2)) = 1>) reaction turns out to be negligible (< ±1%). This observation supports the reaction mechanism as theoretically predicted by Huang et al. [J. Phys. Chem. A 106, 5490 (2002)] that the first step is an intermediate formation with no energy barrier in which C-atom of CH molecule attacks on one O-atom of O(2) molecule at a sideways configuration.

Multidimensional steric effect for the XeF* (B, C) formation in the oriented Xe* ((3)P(2), M(J) = 2) + oriented NF(3) reaction.

Steric effect for the XeF* (B, C) formations in the oriented Xe* ((3)P(2), M(J) = 2) + oriented NF(3) reaction has been observed as a function of the mutual configuration between the molecular orientation and the atomic orientation in the collision frame. Molecular steric opacity function has been determined as a function of the atomic orbital alignment (L(Z)') in the collision frame. The larger reactivity at the side with the smaller reactivity at the molecular axis direction is observed for the XeF* (B, C) channels at each atomic orbital alignment. A good correlation between the shape of the molecular steric opacity function and the molecular geometry of NF(3) is recognized. The L(Z)' selectivity in the molecular steric opacity function is different between the XeF* (B, C) channels; in the sideways direction, the XeF* (B) channel is favorable at L(Z)' = 0, while the XeF* (C) channel is favorable at |L(Z)'| = 1. In contrast, at the molecular axis direction, the XeF* (B) channel is favorable at |L(Z)'| = 1, while the XeF* (C) channel is favorable at L(Z)' = 0. We propose the collision-induced harpoon mechanism for the XeF* (B, C) formation in the Xe* ((3)P(2)) + NF(3) reaction.

Multidimensional molecular steric opacity function for XeCl*(B, C) formation in the oriented Xe* (³P2, MJ = 2) + oriented CCl3F reaction.

The steric effect for the XeCl*(B, C) formations in the oriented Xe* (³P2, MJ = 2) + oriented CCl3F reaction has been observed as a function of the mutual configuration between the molecular orientation and the atomic orbital alignment in the collision frame. Molecular steric opacity functions have been determined as a function of the atomic orbital alignment (M(L)') in the collision frame. The XeCl*(B, C) channels show similar molecular steric opacity functions at M(L)' = 0 but not at |M(L)'| = 1. The large molecular alignment dependence (i.e., the reactivity of the Cl3 end and the F end is comparable, but a very poor reactivity for the sideway) is recognized for the XeCl*(B, C) channels except for the XeCl*(C) channel at |M(L)'| = 1, which shows an almost isotropic molecular orientation dependence. The M(L)' selectivity is different between the XeCl*(B, C) channels. At the molecular axis direction, the XeCl*(B) channel has little M(L)' selectivity whereas the XeCl*(C) channel is significantly favorable at M(L)' = 0. On the other hand, |M(L)'| = 1 is favorable at the sideway for the XeCl*(B, C) channels.

Multidimensional steric effect for the XeBr* (B, C) formation in the oriented Xe*((3)P2, M(J) = 2) + oriented CF3Br reaction.

Steric effect for the XeBr(*) (B, C) formation in the oriented Xe(*)((3)P(2), M(J) = 2) + oriented CF(3)Br reaction has been observed as a function of the mutual configuration between the molecular orientation and the atomic orientation in the collision frame. Molecular steric opacity function has been determined as a function of the atomic orbital alignment (L(Z)(')) in the collision frame. The L(Z)(') selectivity in the molecular steric opacity function is different between the XeBr(*) (B, C) channels: For the XeBr(*) (C) channel, the L(Z)(') = 0 alignment is favorable at the molecular axis direction and the absolute value(L(Z)(')) = 1 alignment is favorable at the sideway direction, whereas for the XeBr(*) (B) channel, the L(Z)(') = 0 alignment is favorable at the sideway direction and the absolute value(L(Z)(')) = 1 alignment is favorable at the molecular axis direction. However, the shape of the steric opacity function for the XeBr(*) (B) channel at the L(Z)(') = 0 (and absolute value(L(Z)(')) = 1) alignment is similar to that for the XeBr(*) (C) channel at the absolute value(L(Z)(')) = 1 (and L(Z)(') = 0) alignment, respectively: A large molecular orientation dependence (i.e., the largest reactivity at the Br-end with the small molecular alignment dependence) is recognized for the XeBr(*) (B) channel at the L(Z)(') = 0 alignment and for the XeBr(*) (C) channel at the absolute value(L(Z)(')) = 1 alignment, whereas a large molecular alignment dependence (i.e., the largest reactivity at the Br-end with the poor reactivity at the sideway) is recognized for the XeBr(*) (B) channel at the absolute value(L(Z)(')) = 1 alignment and for the XeBr(*) (C) channel at the L(Z)(') = 0 alignment. We propose the indirect mechanism for the dark channels (Xe + Br + CF(3)) via the back-electron transfer from the CF(3) segment (or dissociating CF(3)...Br(-)) to Xe(+) as the origin of the significant molecular alignment dependence in the molecular steric opacity function.

Multi-dimensional steric effect for XeI* (B) formation in the oriented Xe* ((3)P(2), M(J) = 2) + oriented CH(3)I reaction.

Multi-dimensional steric effect for the XeI* (B) formation in the oriented Xe* ((3)P(2), M(J) = 2) + oriented CH(3)I reaction has been observed as a function of the mutual configuration between the molecular orientation and the atomic alignment in the collision frame. The molecular steric opacity function has been determined as a function of the atomic orbital alignment. The large molecular orientation dependence (i.e., the largest reactivity at the I-end and the large difference in the reaction probability between the I-end and the CH(3)-end) and the large molecular alignment dependence (the poor reactivity at the sideway) is recognized for each atomic orbital alignment. In addition, a clear correlation between the molecular orientation and the atomic orbital alignment is recognized (i.e., the L(Z)' = 0 atomic orbital alignment is favorable for the molecular axis direction, while the |L(Z)'| = 1 atomic orbital alignment is favorable for the sideway direction).

Steric effect in the energy transfer reaction of oriented Kr (3P2, MJ = 2) + CO.

Atomic alignment effect for the formations of CO (a' (3)Sigma(+)) and CO (d (3)Delta) in the energy transfer reaction of oriented Kr ((3)P(2), M(J) = 2) + CO has been measured at a collision energy of 0.07 eV. The emission intensities of CO (a' (3)Sigma(+)) and CO (d (3)Delta) were similarly highly enhanced when the electron angular momentum of Kr ((3)P(2)) is aligned perpendicular to the relative velocity vector. We observed the analogous atomic alignment effect between the CO (a' (3)Sigma(+)) and CO (d (3)Delta) formations. That is, the |M(J)'| = 2 magnetic substate in the collision frame is significantly less reactive than the other M(J)' states. In addition, the large difference of the cross section (sigma(Sigma)/sigma(Pi) approximately 2.0) between the Sigma- and Pi-configuration of the unpaired 4p orbital of Kr ((3)P(2)) is recognized.

Collision energy dependence of the rotational-state-resolved cross section in the CH (v = 0, J, F(i)) + O(2) --> OH(A) + CO reaction.

A velocity variable rotational-state-selected CH (v = 0, J, F(i)) beam has been prepared by using an electric hexapole and applied to the CH (v = 0, J, F(i)) + O(2) --> OH(A) + CO reaction. The CH rotational-state-resolved reaction cross sections have been determined under the beam-cell condition at the collision energy range of 0.06-0.18 eV. The N = 2 rotational states are 2-3 times more reactive than the other states (N = 1, 3). In addition, we observed a noticeable difference in the collision energy dependence of the cross section between the CH rotational states. The reaction cross section for the N = 2 states has a gentle negative dependence on collision energy, while, the reaction cross section for the N = 1 states has a positive dependence on collision energy.

Multidimensional steric effects for the XeI* (B, C) formations in the oriented Xe* (3P(2),M(J) = 2) + oriented CF3I reaction.

Steric effects for the XeI(*) (B) and XeI(*) (C) formations in the oriented Xe(*) ((3)P(2),M(J)=2)+oriented CF(3)I reaction have been observed as a function of the mutual configuration between molecular orientation and atomic alignment in the collision frame. The mutual configuration exercises the significant influences on the stereoanisotropy for both the reactivity and the branching to the XeI(*) (B) and XeI(*) (C) channels.

Correlation between the atomic alignment and the alignment of XeX* (B, C) rotation in the reactions of oriented Xe ((3)P(2), M(J) = 2) + halogen (X)-containing molecules.

The polarization of the XeX* (B) and XeX* (C) emissions in the reactions of oriented Xe* ((3)P(2), M(J) = 2) + halogen (X)-containing molecules (CCl(4), CF(3)Br, CF(3)I, CH(3)I, NF(3)) has been measured as a function of each magnetic M(J)' substate in the collision frame. The parallel polarization of the XeX* (B, C) 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(M(J)')) of the XeX* (B, C) rotation is found to be extremely different between the XeX* (B) and XeX* (C) channels: For XeX* (B), A(M(J)') is highest for the M(J)' = 0 state, except CCl(4), whereas the |M(J)'| = 2 states give the highest A(M(J)') for XeX* (C). Alternatively, the correlation between the configuration (L(Z)') of the inner 5p orbital and the L(Z)'-dependent alignment (A(L(Z)')) of the XeX* (B, C) rotations is revealed. The collision with |L(Z)'| = 1 causes a similar positive alignment A(L(Z)') for the XeX* (B) and XeX* (C) channels. The alignment A(L(Z)') at the collision with |L(Z)'| = 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 CF(3)I, that is, A(L(Z)'=0) approximately 0, whereas it induces the higher positive A(L(Z)') of XeX* (B). The different M(J)' dependence on the alignment of the XeX* (B, C) 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.

Atomic alignment effects for the formation of excimers RgX* (B, C) in the reaction of oriented Rg ((3)P2, M(J) = 2) (Rg = Xe, Kr, Ar) + halogen(X)-containing molecules.

Atomic alignment effects for the formation of excimers, RgX* (B, Omega = 1/2) and RgX* (C, Omega = 3/2), in the reaction of Rg ((3)P(2)) (Rg = Xe, Kr, Ar) with halogen (X)-containing molecules (RX) (CH(3)I, CF(3)I, CF(3)Br, NF(3), CHBr(3), CHCl(3), CCl(3)F, and CCl(4)) have been measured by using an oriented Rg ((3)P(2), M(J) = 2) atomic beam at a collision energy of approximately 0.07 eV. The emission intensities for RgX* (B, C) have been measured as a function of the magnetic orientation field direction in the collision frame. The reactant (RX) dependence of the atomic alignment effect is extremely different between the RgX* (B) and the RgX* (C) channels. For RgX* (C), an analogous atomic alignment effect is commonly observed despite the difference of RX and Rg. In contrast, for RgX* (B), the atomic alignment effect shows a diverse dependence on RX and Rg.

Atomic alignment effect on the branching to ArCl* and CCl2* formation in the reaction of oriented Ar(3P2,MJ=2) + CCl4.

Atomic alignment effects for the formation of ArCl*(C) and CCl2*(A) in the reaction of Ar((3)P 2) + CCl 4 have been measured by using an oriented Ar( (3)P2, M J=2) beam at a collision energy of 0.08 eV. The emission intensity for ArCl*(C) and CCl2*(A) has been measured as a function of the magnetic orientation field direction in the collision frame. A significant atomic alignment effect is observed for the atom transfer process [ArCl*(C) formation]. Formation of ArCl*(C) is modestly enhanced when the electron angular momentum of the Ar((3)P 2) reactant is aligned along the relative velocity vector, while the excitation transfer process [CCl2*(A) formation] shows little alignment effect.