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Titolo: The acetylene bending spectrum at similar to 10000 cm(1): Quantum assignments in the midst of classical chaos
Autore: Jung, C; Taylor, HS; Jacobson, MP;
 Indirizzi:
 Univ So Calif, Los Angeles, CA 90089 USA Univ So Calif Los Angeles CA USA90089 o Calif, Los Angeles, CA 90089 USA UNAM, Ctr Ciencias Fis, Cuernavaca 62251, Morelos, Mexico UNAM CuernavacaMorelos Mexico 62251 s, Cuernavaca 62251, Morelos, Mexico Phys & Theoret Chem Lab, Oxford OX1 3QZ, England Phys & Theoret Chem Lab Oxford England OX1 3QZ , Oxford OX1 3QZ, England
 Titolo Testata:
 JOURNAL OF PHYSICAL CHEMISTRY A
fascicolo: 4,
volume: 105,
anno: 2001,
pagine: 681  693
 SICI:
 10895639(20010201)105:4<681:TABSAS>2.0.ZU;2C
 Fonte:
 ISI
 Lingua:
 ENG
 Soggetto:
 INTRAMOLECULAR VIBRATIONAL REDISTRIBUTION; DISPERSED FLUORESCENCESPECTRA; SEMICLASSICAL QUANTIZATION; ALGEBRAIC QUANTIZATION; PERTURBATIONTHEORY; PERIODICORBITS; DYNAMICS; STATE; ENERGY; SPECTROSCOPY;
 Tipo documento:
 Article
 Natura:
 Periodico
 Settore Disciplinare:
 Physical, Chemical & Earth Sciences
 Citazioni:
 28
 Recensione:
 Indirizzi per estratti:
 Indirizzo: Taylor, HS Univ So Calif, Los Angeles, CA 90089 USA Univ So Calif Los Angeles CA USA 90089 s Angeles, CA 90089 USA



 Citazione:
 C. Jung et al., "The acetylene bending spectrum at similar to 10000 cm(1): Quantum assignments in the midst of classical chaos", J PHYS CH A, 105(4), 2001, pp. 681693
Abstract
A combination of quantum mechanics, semiclassical mechanics, and nonlinearclassical dynamics is used to extract the detailed internal molecular motions that underly the quantum eigenstates of acetylene with 16 quanta of total bend excitation. No potential energy surface is used; rather, the statesare represented by an algebraic effective Hamiltonian that has been extensively refined against experimental data. The classical mechanical analysis reveals widespread chaos, but the quantum mechanical structure is surprisingly regular. Specifically, all 81 quantum states can be assigned a pair of semiclassical quantum numbers that reveal the underlying classical motions associated with each state. These classical motions range continuously between limitingcase motions that we refer to as local bend (one hydrogen bending) and counterrotation (the two hydrogens undergoing circular motions inplanes perpendicular to the CC axis). The first reason that the regularityin the quantum structure was previously undetected is that the identification of regular nodal coordinates, if any exist, of quantum wave functions in a multidimensional (i.e., greater than two dimensions) space is generallya difficult task; our success here was made possible by the identificationin a reduced twodimensional (2D) space of two families of periodic orbits(dynamic modes) which evolve with energy. Every quantum state reflects thequantization of the two dynamic mode system. The second reason for the undetected regularity is that the regular sequences of quantum levels that we have identified are interspersed among each other in energy, thus giving the appearance of a complex, unassignable spectrum.
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Documento generato il 12/07/20 alle ore 05:50:56