TY - JOUR

T1 - Intramolecular coupling between non-penetrating high molecular Rydberg states

AU - Bixon, M.

AU - Jortner, Joshua

PY - 1996/10/1

Y1 - 1996/10/1

N2 - We address a central question in the realm of the dynamics of high-n (= 40-250) Rydberg states of diatomics and large molecules. What is the coupling responsible for the 'global' l mixing, which results in the breakdown of the n 3 scaling law for the non-radiative lifetimes and for the lifetime lengthening (by two to four orders of magnitude) of these states? To explore the implications of intramolecular interactions on l mixing and on electronic-rotational energy exchange we analysed the intramolecular couplings of the ion core dipole, quadrupole and (anisotropic) polarizability with a non-penetrating (l⩾ 3) Rydberg electron, in conjunction with the energy gaps between proximal pairs of energy levels. Calculations of the energy gaps and the couplings were performed for the high-n non-penetrating Rydberg states of NO and for model 'light' (B = 19 cm-1) and 'heavy' (B = 0⋅05 cm-1) polar molecules. All the intramolecular interactions are of the form of a power law proportional to l -η, with η being determined by the nature of the long-range coupling, by the l dependence of the quantum defects for multipole couplings and by the l dependence of angular integrals. We established a bottleneck effect for the intramolecular couplings between non-penetrating (l⩾3) states. For n-and N+-changing dipole, quadrupole and polarizability interactions the energetics ofthe proximalpairs of levels, in conjunction with the bottleneck effect, the |n, l, N +, N>-|n', l', N +', N>, l (⩾ 3) couplings (with n ╪ n') and the electronic-rotational energy exchange. For n-and N +-conserving quadrupole and polarizability interactions, the l (⩾ 3) mixing (which prevails only for lN ++ N) is also prohibited by the bottleneck effect. 'Global' intramolecular l mixing (with both n ╪ n' and n = n') in diatomics and in large molecules is precluded, implying that the dramatic lengthening of the non-radiative lifetimes of high-n Rydberg states can be induced only by exterior electric field coupling.

AB - We address a central question in the realm of the dynamics of high-n (= 40-250) Rydberg states of diatomics and large molecules. What is the coupling responsible for the 'global' l mixing, which results in the breakdown of the n 3 scaling law for the non-radiative lifetimes and for the lifetime lengthening (by two to four orders of magnitude) of these states? To explore the implications of intramolecular interactions on l mixing and on electronic-rotational energy exchange we analysed the intramolecular couplings of the ion core dipole, quadrupole and (anisotropic) polarizability with a non-penetrating (l⩾ 3) Rydberg electron, in conjunction with the energy gaps between proximal pairs of energy levels. Calculations of the energy gaps and the couplings were performed for the high-n non-penetrating Rydberg states of NO and for model 'light' (B = 19 cm-1) and 'heavy' (B = 0⋅05 cm-1) polar molecules. All the intramolecular interactions are of the form of a power law proportional to l -η, with η being determined by the nature of the long-range coupling, by the l dependence of the quantum defects for multipole couplings and by the l dependence of angular integrals. We established a bottleneck effect for the intramolecular couplings between non-penetrating (l⩾3) states. For n-and N+-changing dipole, quadrupole and polarizability interactions the energetics ofthe proximalpairs of levels, in conjunction with the bottleneck effect, the |n, l, N +, N>-|n', l', N +', N>, l (⩾ 3) couplings (with n ╪ n') and the electronic-rotational energy exchange. For n-and N +-conserving quadrupole and polarizability interactions, the l (⩾ 3) mixing (which prevails only for lN ++ N) is also prohibited by the bottleneck effect. 'Global' intramolecular l mixing (with both n ╪ n' and n = n') in diatomics and in large molecules is precluded, implying that the dramatic lengthening of the non-radiative lifetimes of high-n Rydberg states can be induced only by exterior electric field coupling.

UR - http://www.scopus.com/inward/record.url?scp=0343355141&partnerID=8YFLogxK

U2 - 10.1080/002689796173787

DO - 10.1080/002689796173787

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AN - SCOPUS:0343355141

SN - 0026-8976

VL - 89

SP - 373

EP - 401

JO - Molecular Physics

JF - Molecular Physics

IS - 2

ER -