Abstract book - Prof. Per Jensen, Ph.D. - Bergische Universität ...

170 Poster session, J7Quantum-classical Rydberg electron dynamics in a polar moleculeP. John Shepherd 1 , Vladislav E. Chernov 2,3 , Dmitry L. Dorofeev 3 , M.Yu. Knyazev 31 School of Physics, University of Exeter, Stocker Road, Exeter, UK, EX4 4QL,p.j.shepherd@exeter.ac.uk; 2 J.Heyrovský Institute of Chemical Physic, Praha 8,Dolejškova 3, 18200, chernov@jh-inst.cas.cz; 3 Voronezh State University, Voronezh394006, Russia, e-mail: chernov@niif.vsu.ruShepherd P.J.Chernov V.E.Dorofeev D.L.Knyazev M.Yu.The classical picture of the coupling between the electronic and rotational degrees offreedom for molecular Rydberg states has proved effective in the analysis of a wide rangeof phenomena, such as chaotic auto-ionization of molecular Rydberg states [1] and timeevolution of Rydberg wave packets [2]. The quantum description of a Rydberg electron ina polar molecule is based on the exactly solvable [3] “Coulomb + point dipole”Hamiltonian. Besides the projection of the electron orbital angular momentum on to thedipole axis, the noninteger quasi-angular momentum l , ( d) l l, ( d), wherel, ( d)is the quantum defect), is the conserved quantum number appearing in the2 2eigenvalue ( 1)of the nonspherical operator L 2dcoswith eigenvaluesenumerated by the integer l. The classical Hamiltonian can be written in terms of the actionvariables as2 21( I I) 3I2Hel 2Ir I I , ( d) 2 ,where, for small d, , ( d)d is the54( I I)classical counterpart of the quantum defect l, ( d). It is remarkable that for small d theycoincide for large (quasiclassical) I I[3].The dynamics of very high Rydberg states displays rotational–electronic nonadiabaticinteractions (l-decoupling [4], or inverse Born–Oppenheimer dynamics corresponding totransition from Hund cases a, b to case d [5]). The criterion for breakdown of the rotationalBorn–Oppenheimer approximation is the same in the quantum and the classical picture: thecore rotation frequency B N should be high compared with the precession frequency p(not with the Keplerian frequency K ), i.e., the rotational l-decoupling can occur at2effective quantum numbers 1 3* Δ Z B N , where Δ l 1, l, . Sincethe quantum defects of high-l Rydberg levels are small, the * values can be lower thanthose often used [4,5] when one assumes Δ 1.References[1] F. Benvenuto, G. Casati, D. L. Shepelyansky, Phys. Rev. Lett. 72, 1818 (1994)[2] H. H. Fielding, Ann. Rev. Phys. Chem. 56, 91 (2005)[3] B. A. Zon, Zh. Eksp. Teor. Fiz. 102, 36 (1992) [Sov. Phys. JETP 75, 19 (1992)]; J. K.G. Watson, Mol. Phys. 81, 227 (1994)[4] R. W. Field, C.M. Gittins, N. A. Harris, Ch. Jungen, J. Chem. Phys. 122, 184314(2005)[5] B. A. Zon, Phys. Lett. A203, 373 (1995); A.V. Danilyan, V.E. Chernov, Opt.Spectrosc. 104, 21 (2008)