Nonadibatic transition due to potential energy curve crossing is one of the most important mechanisms to effectively induce electronic transitions in collisions [1].   Theory of nonadiabatic transitions dates back to 1932, when the pioneering works were published by Landau [2], Zener [3] and Stueckelberg [4]. Since then  numerous papers by many authors have been devoted to this subject [1].

Here we have proposed a general method for finding the exact analytical solution for the two state curve crossing problem in presence of a delta function coupling [4].  Our solution is quite general and  is valid for any potential. This method is used to calculate the effect of curve crossing on electronic absorption spectrum and resonance Raman excitation profile. We have extended our model to deal with general one dimensional multi-channel curve crossing problems.

References

[1] H. Nakamura, Int. Rev. Phys. Chem. 407, 57    (2000).

[2] L. D. Landau, Phys.  Zts. Sowjet.. 2, 46 (1932).

[3] C. Zener, Proc..Roy. Soc. A  137, 696 (1932).

[4] E. C. G. Stuckelberg, Helv. Phys.  Acta. 5, 369 (1932).

[5] A. Chakraborty, Mol. Phys., 107,165 (2009).

[6] A. Chakraborty, Mol. Phys., 107, 2459 (2009).

[7] A. Chakraborty, Mol. Phys.,109, 429 (2011).

[8] Diwaker & A. Chakraborty, Mol. Phys. (in press) [2012].

[9] Diwaker & A. Chakraborty, Mol. Phys. (in press) [2012].

[10] Diwaker & A. Chakraborty, Mol. Phys., [under revision] (2012).

    Non-adiabatic Transition