Nonadiabatic interaction

B. H. Lengsfield and D. R. Yarkony, Nonadiabatic Interactions Between Potential Energy Surfaces Theory and Applications, in State-Selected and State to State Ion-Molecule Reaction Dynamics Part 2 Theory, M. Baer and C.-Y. Ng, eds., John Wiley Sons, Inc., New York, 1992, Vol, 82, pp. 1-71. 

Lengsfield BH, Yarkony DR (1992) Nonadiabatic interactions between potential energy surfaces theory and applications. In Baer M, Ng CY (eds) State-selected and state-to-state ion-molecule reaction dynamics part 2 theory, Vol. 82 of Advances in Chemical Physics, John Wiley and Sons, New York, p 1-71. 

Fig. 10. The emerging picture of electronically nonadiabatic interactions of NO molecule scattering at a metal surfaces. Transition from the ground electronic state to an anionic state which is strongly attractive to the metal surface can be accomplished by high translational energy when vibrational excitation is low (black trajectory). When vibrational motion is highly excited, even low translational energies allow transition of the anionic state (red trajectory). Recently, Monte-Carlo wavepacket calculations have been carried out which tend to support this picture.63...

Hydroxyl radical (OH) is a key reactive intermediate in combustion and atmospheric chemistry, and it also serves as a prototypic open-shell diatomic system for investigating photodissociation involving multiple potential energy curves and nonadiabatic interactions. Previous theoretical and experimental studies have focused on electronic structures and spectroscopy of OH, especially the A2T,+-X2n band system and the predissociation of rovibrational levels of the M2S+ state,84-93 while there was no experimental work on the photodissociation dynamics to characterize the atomic products. The M2S+ state [asymptotically correlating with the excited-state products 0(1 D) + H(2S)] crosses with three repulsive states [4>J, 2E-, and 4n, correlating with the ground-state fragments 0(3Pj) + H(2S)[ in... 

First of all, the theory presented is based on a few assumptions, which, while valid for the molecular systems considered in the literature so far, need to be care-fidly examined in every specific case. As mentioned in Section 8.3, we assume that the effects of external fields on the kinetic energy operator for the relative motion are negligible and that the interactions with electromagnetic fields are independent of the relative separation of the colliding particles. In addition, we ignore the nonadiabatic interactions that may be induced by external fields and that, at present, cannot be rigorously accounted for in the coupled channel calculations. 

There are several nonadiabatic interactions (see the appendix), for example, electron-vibration coupling and spin-orbit interaction. The electron-vibration interaction is described by the operator ... 

The Born-Oppenheimer (BO) description is not exact. The deviation from the BO approximation can be treated as an additional nonadiabatic interaction. This interaction does not depend on time and can be the origin of radiationless transitions. Moreover, the nonadiabatic interaction is a main mechanism for one kind of indirect photodissociation, namely, photopredissociation of Type I (electronic predissociation). 

In this appendix the expression describing the nonadiabatic interaction (72,73) is derived. The method of derivation (29) is somewhat different from the usual we focus directly on the separation of the nonadiabatic term in the Hamiltonian. 

M. Desouter-Lecomte and J. C. Lorquet,/. Chem. Phys., 71,4391 (1979). Nonadiabatic Interactions in Unimolecular Decay. IV. Transition Probability as a Function of the Massey Parameter. 

The aforementioned E — D nonadiabatic interactions also lead to efficient, i.e., femtosecond internal conversion processes which we now briefly address. The presence of such processes is indicated indirectly by experimental studies, where Bz+ has been prepared initially in the E state, but fragmentation been found to occur via lower (even the X) electronic states [45,46]. To describe this non-radiative decay... 

E.E.Nikitin, On the interelectronic and nonadiabatic interactions in long-chain... 

We have focused on the charge transport at interfaces and nonadiabatic interactions between injected electrons and nuclear motions. Our purpose is to establish practical models, which enable us to perform ah initio calculations. We adopted the NEGF formalism, and developed theoretical models combined with a practical ah initio scheme by means of DFT. We chose two systems as examples, the E-M-E junction and photoreaction on metal surfaces. 

Schaller R. D., Pietryga 1. M., Goupalov S. V., Petruska M. A., Ivanov S. A. and Klimov V. I. (2005c), Breaking the phonon bottleneck in semiconductor nanocrystals via multiphonon emission induced by intrinsic nonadiabatic interactions , Phys. Rev. Lett. 95, 196401. 

There has been some work on semi-classical quantization of the linear Jahn-Teller Hamiltonian (2.2) [41,42]. The quantization scheme which bears the closest relation to the present wave packet treatment involved the calculation of classical trajectories while slowly turning on the nonadiabatic interaction [41(a)]. The main emphasis of that work was the development of a method for obtaining energy levels in molecules with nonadiabatic dynamics which might then be applied to larger multimode systems. 

The basic idea of the PSS method is to start from the molecular wave-function and to take the nonadiabaticity as a perturbation. However, in the case of symmetrical resonance the energy splitting of a and corresponding u state gives the transition probability even when the nonadiabatic interaction is negligibly small. The Schrodinger equation describing the whole system composed of two atoms is... 

E.E.Nikitin, On the interelectronic and nonadiabatic interactions in long-chain molecules, in Voprosy Kvantovoy Khimii, Leningrad, University Press, 1963, p.lOO. 

For a polyatomic molecule with n degrees of freedom, the crossing point is replaced by a crossing seam in a ( - l)-dimensional space or, for certain symmetric systems, is replaced by canonical or Jahn-Teller intersection (see chapter 3). Such nonadiabatic interactions for polyatomics have been studied extensively by Lorquet and co-workers (Desouter-Lecomte et al., 1979 Dehareng et al., 1983 Desouter-Lecomte et al., 1985 Barbier et al., 1984). 

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