Assigning spectra of chaotic molecules with diabatic correlation diagrams

Journal Article · Fri Nov 01 04:00:00 EST 1996 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.472593· OSTI ID:392669

Rose, J P; Kellman, M E ^[1]

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1. Department of Chemistry, University of Oregon, Eugene, Oregon 97403 (United States)

An approach for classifying and organizing spectra of highly excited vibrational states of molecules is investigated. As a specific example, we analyze the spectrum of an effective spectroscopic fitting Hamiltonian for H{sub 2}O. In highly excited spectra, multiple resonance couplings and anharmonicity interact to give branching of the {ital N} original normal modes into new anharmonic modes, accompanied by the onset of widespread chaos. The anharmonic modes are identified by means of a bifurcation analysis of the spectroscopic Hamiltonian. A diabatic correlation diagram technique is developed to assign the levels with approximate {open_quote}{open_quote}dynamical{close_quote}{close_quote} quantum numbers corresponding to the dynamics determined from the bifurcation analysis. The resulting assignment shows significant disturbance from the conventional spectral pattern organization into sequences and progressions. The {open_quote}{open_quote}dynamical{close_quote}{close_quote} assignment is then converted into an assignment in terms of {open_quote}{open_quote}nominal{close_quote}{close_quote} quantum numbers that function like the {ital N} normal mode quantum numbers at low energy. The nominal assignments are used to reconstruct, as much as possible, an organization of the spectrum resembling the usual separation into sequences and progressions. {copyright} {ital 1996 American Institute of Physics.}

• DOE Contract Number: FG06-92ER14236
• OSTI ID: 392669
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 17 Vol. 105; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ABSORPTION SPECTROSCOPY
ANHARMONICITY
BIFURCATION
CHAOTIC SYSTEMS
CORRELATION FUNCTIONS
EXCITED STATES
FERMI RESONANCE
MOLECULES
VIBRATIONAL STATES
WATER