Excitonic interactions in naphthalene clusters

Journal Article · Thu Jan 25 04:00:00 EST 1990 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100365a042· OSTI ID:6660944

Wessel, J E; Syage, J A ^[1]

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1. Aerospace Corp., Los Angeles, CA (USA)

Well-resolved vibronic spectra, recorded by resonance two-photon ionization, are analyzed for cold naphthalene cluster species. Spectra for isotopically pure tetramers and both pure and mixed isotopic trimer clusters provide information on resonant (excitonlike) interactions. An analysis of the spectra suggests that the tetramer geometry resembles bulk crystalline naphthalene, whereas the trimer structure minimizes direct contact interactions. Cluster geometry is similar in ground and excited states of these clusters and there is no direct evidence for rapid dynamics in the excited states, nor is there evidence of multiple geometric conformations. Analysis of the isotopically mixed trimers suggests a preference for the HDH conformation, rather than HHD. An empirical weak interaction model provides a successful description of the observed spectra. Excitonic splittings are approximately proportional to dipole transition strengths for the vibronically induced spectra, whereas low-intensity allowed origin transitions exhibit splittings that greatly exceed dipolar contributions. Both results indicate that the long-range intermolecular potential exceeds simple estimates. This method of analysis may be applicable to studies of larger clusters, providing new information on size-dependent structure and dynamics.

• DOE Contract Number: FG03-86ER60391
• OSTI ID: 6660944
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 94:2; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AROMATICS
CALCULATION METHODS
CLUSTER MODEL
CONDENSED AROMATICS
DATA
DATA ANALYSIS
DYNAMICS
ENERGY LEVELS
EXCITED STATES
EXCITONS
EXPERIMENTAL DATA
GEOMETRY
HYDROCARBONS
INFORMATION
IONIZATION
MATHEMATICAL MODELS
MATHEMATICS
MEASURING INSTRUMENTS
MEASURING METHODS
MECHANICS
NAPHTHALENE
NUCLEAR MODELS
NUMERICAL DATA
ORGANIC COMPOUNDS
QUASI PARTICLES
VIBRATIONAL STATES