Ab initio and MM3 studies of the conformational structures of naphthalene trimer: Comparison with experiment

Journal Article · Thu Mar 18 04:00:00 EST 1999 · Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory

DOI:https://doi.org/10.1021/jp984374e· OSTI ID:351494

Gonzalez, C ^[1]; Lim, E C ^[2]

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1. National Inst. of Standards and Technology, Gaithersburg, MD (United States). Physical and Chemical Properties Div.
2. Univ. of Akron, OH (United States). Dept. of Chemistry

An ab initio study of the ground-state conformational geometries of the naphthalene trimer, (C{sub 10}H{sub 8}){sub 3}, has been made at the MP2/6-31G and MP2/6-31 + G/MP2/6-31G levels of theory. The lowest-energy structure was found to be the edge-to-face cyclic (C{sub 3h}) geometry in which the three equivalent naphthalene moieties are arranged with their long in-plane axes parallel. The fully optimized MP2/6-31G structure has a center-to-center intermoiety distance of 4.986 {angstrom} and an angle of 48.0{degree} between the short in-plane axis of a naphthalene moiety and the line connecting the center-of-mass of the monomer with that of the trimer. The computed rotational constants (B = 0.00555 and C = 0.00468 cm{sup {minus}1}) for the oblate symmetric top are essentially identical to the experimental values (B = 0.00557 and C = 0.00470 cm{sup {minus}1}) obtained from rotational coherence spectroscopy (see the following Letter by Benharash, Gleason, and Felker). Molecular mechanics (MM3) calculations also yield the same C{sub 3h} trimer as the minimum-energy structure. The result suggests that, with the optimization and reparametrizations of the existing force fields to fit the ab initio (or experimental, where available) geometry/energy for selected dimers and small clusters, it may be possible to develop accurate and practical intermolecular potentials for aromatic clusters.

• Sponsoring Organization: USDOE
• OSTI ID: 351494
• Journal Information: Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Journal Name: Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory Journal Issue: 11 Vol. 103; ISSN 1089-5639; ISSN JPCAFH
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BOND LENGTHS
ENERGY LEVELS
MOLECULAR MODELS
MOLECULAR STRUCTURE
NAPHTHALENE
POLYMERS
QUANTUM MECHANICS