Infinite order sudden approximation

Snider R. F., Coombe D. A. Kinetic cross sections in the infinite order sudden approximation, J. Phys. Chem. 86, 1164-74 (1982). 

Goldflam R., Green S., Kouri D. J. Infinite order sudden approximation for rotational energy transfer in gaseous mixtures, J. Chem. Phys. 67, 4149-61, (1977). 

Infinite-order sudden approximation (IOSA), electron nuclear dynamics (END), molecular systems, 345-349 Initial relaxation direction (IRD), direct molecular dynamics, theoretical background, 359-361 Inorganic compounds, loop construction, photochemical reactions, 481-482 In-phase states ... 

By using this approach, it is possible to calculate vibrational state-selected cross-sections from minimal END trajectories obtained with a classical description of the nuclei. We have studied vibrationally excited H2(v) molecules produced in collisions with 30-eV protons [42,43]. The relevant experiments were performed by Toennies et al. [46] with comparisons to theoretical studies using the trajectory surface hopping model [11,47] (TSHM). This system has also stimulated a quantum mechanical study [48] using diatomics-in-molecule (DIM) surfaces [49] and invoking the infinite-order sudden approximation (IOSA). 

Atabek, O., Beswick, J.A., and Delgado-Barrio, G. (1985). A test of the rotational infinite order sudden approximation in molecular fragmentation, J. Chem. Phys. 83, 2954-58. 

Delgado-Barrio, G., Mareca, P., Villarreal, P., Cortina, A.M., and Miret-Artes, S. (1986). A close-coupling infinite order sudden approximation (IOSA) to study vibrational predissociation of the Hel2 van der Waals molecule, J. Chem. Phys. 84, 4268-4271. 

Kulander, K.C. and Light, J.C. (1986). Theory of polyatomic photodissociation in the reactive infinite order sudden approximation Application to the Rydberg states of H3, J. Chem. Phys. 85, 1938-1949. 

Semiclassical Perturbation—Infinite Order Sudden Approximation. 

Such an approximation, which is a derivative of the exact formalism presented by Kuppermann Schatz and Baer (KSB) [3] is described in this paper. Use is made of the Infinite order sudden approximation (lOSA) as applied in the inelastic case but contains significant changes whereas in the inelastic case one has to treat one arrangement channel at a time, in the case of exchange at least two channels are... 

While only exact ID calculations are feasible for the present time, approximate 3D quantum treatments can be used. The Infinite Order Sudden Approximation (lOSA) appears particularly well suited to study the dissociation of a heavy diatomic molecule collided by a light atom ... 

Abstract. We present an overview of the influence of C.F. Curtiss on the theory of molecular collisions, as exemplified by the title paper. Both authors were graduate students of Curtiss and, as such, were strongly influenced by his ideas and approaches to theoretical chemistry. This resulted in a subsequent collaboration that provided the rigorous basis for understanding the success of the so-called centrifugal sudden and energy sudden approximations (the two combined being the infinite order sudden approximation). 

Key words Centrifugal sudden approximation - Infinite order sudden approximation - Sudden approximations -Inelastic collisions - Rotationally inelastic collisions... 

VT Energy Transfer. Breathing Sphere Model and Infinite Order Sudden Approximation. 

A simple well-known extension of a collinear Landau-Teller model is provided by the breathing sphere (BSP) model of Schwartz, Slawsky and Herzfeld [13] which fully retains the Landau-Teller exponential factor. More consistent treatment, which approximately takes into account the anisotropic character of the atom-molecule interaction, is based on the so-called infinite order sudden approximation (lOSA) [14] with respect to rotational transitions that accompany the vibrational transition. Within this approximation the rotation of the relaxing molecule plays the role of a spectator, which insignificantly modifies the exponent in Eq. (8) through quite unimportant redefinition of a. If, in addition, the quasiclassical correction to the semiclassical Landau-Teller exponent is small and the effect of the attractive part of the potential is weak, one can write the following simple expression for the deactivation rate constant within BSP or lOSA approximation ... 

ABSTRACT. Total differential cross section (DCS) measurements in the thermal energy range have been carried out for Ne-02/ Ne-NO, Ar-O, Ar-N2 He-Cl2 Ne-Cl2f and Ar-Cl2 under high-resolution conditions which nave always permitted to resolve the diffraction and/or rainbow oscillations. Reliable full anisotropic potential energy surfaces have been derived by also simultaneously fitting all other available experimental properties in a multiproperty fashion within the framework of the infinite-order-sudden approximation, which has been shown to be accurate under the present experimental conditions. Information on the anisotropy of the interaction is obtained from the quenching of the diffraction and rainbow structure in the total DCS. 

Using a Rotational Infinite Order Sudden Approximation [RIOSA) to describe the exiting contmua. X- -BC[v, j ) yielded in the vibrational predissociation of X BC complexes, we outline a fitting procedure of the van der Waals interaction to get agreement with the available experimental data. Assuming an additive pairwise model of Lennard-Jones or Morse atom-atom functional forms, reasonable parameters are obtained under a low computational cost for the He ICl[B) and Ar Cl2[B) systems. 

The above treatment of linearly driven vibrations has been thoroughly tested by calculations of Li ions scattering from N, [62], for which there is available a wealth of experimental data [87, 120] as well as independent theoretical studies. For instance, Secrest et al. did a fully-quantal study using the infinite-order sudden approximation to simplify the rotational problem [135] Billing classically treated the relative and rotational motions while describing vibrations quantum mechanically by means of eigenfunction expansions with time-dependent coefficients [HI] in addition, purely classical simulations have also been performed for Li -N, [121, 122], We first summarize the comparison between our TCF and Billing s semiclassical results, and then illustrate a TCF analysis of experimental measurements. 

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