Angular distributions dissociation products

Since the velocities and angular distributions of products from collisional dissociations at low incident-ion energies have generally not been determined, the precise mechanism by which the products are formed is unknown. Thus in the collisional dissociation of H2+ with helium as the target gas, H+ may result from dissociation of H2+ that has been directly excited to the vibrational continuum... 

Spectroscopic detection of the photoffagment can usually be done in a manner that is sensitive to its internal state and can therefore determine the state distribution of the product. When the Doppler detuning of the spectroscopic transition can be determined, the angular distribution of products in different states can be extracted. For, say, the diatomic product from the dissociation of a triatomic molecule this can provide a wealth of information. Nor is there excessive redim-dancy. Different vibrational final states and even different rotational states of the same vibrational ladder can have interestingly different angular distributions. 

The angular distributions of the 0(3P2) fragments show the degree of correlation between the product recoil velocity (v) with the electric vector of the dissociating light and are typically characterized by the lab frame anisotropy parameter (/ ) given in the equation,52,53... 

Ormerod et al. (780) have studied the photolysis of KI with pulsed polarized light of wavelength 3472 A. From the angular distribution of the product I atoms dissociated from a molecular beam of KI, they have concluded that the recoil I atom direction is nearly perpendicular to the electric vector of the polarized light. The results suggest a transition from the ionic ground state to a neutral excited state. 

Velocity and angular distribution measurements of the product ions from collision-induced dissociation have provided additional information concerning the mechanisms of these processes and the nature of the reactant and product states involved.380 62,208 213"218 The experimental results obtained at relatively high incident-ion energies are generally... 

The photodissociation process takes place most frequently at excitation of the molecule to a non-bonded state, with subsequent dissociation into products. Since the angular part of the transition probability, according to Chapter 2, is still dependent on the mutual orientation of the E-vector of the initiating light beam and on the transition dipole moment d, one may expect spatial anisotropy of angular momenta distribution both in the dissociation products and in the set of molecules which remains undestroyed. 

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