Electron correlations and two-photon states in polycyclic aromatic hydrocarbon molecules

A peculiar role of geometry

Karan Aryanpour, Alok Shukla, Sumitendra Mazumdar

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

We present numerical studies of one- and two-photon excited states ordering in a number of polycyclic aromatic hydrocarbon molecules: coronene, hexa-peri-hexabenzocoronene, and circumcoronene, all possessing D6h point group symmetry versus ovalene with D2h symmetry, within the Pariser-Parr-Pople model of interacting π-electrons. The calculated energies of the two-photon states as well as their relative two-photon absorption cross-sections within the interacting model are qualitatively different from single-particle descriptions. More remarkably, a peculiar role of molecular geometry is found. The consequence of electron correlations is far stronger for ovalene, where the lowest spin-singlet two-photon state is a quantum superposition of pairs of lowest spin triplet states, as in the linear polyenes. The same is not true for D6h group hydrocarbons. Our work indicates significant covalent character, in valence bond language, of the ground state, the lowest spin triplet state and a few of the lowest two-photon states in D2h ovalene but not in those with D6h symmetry.

Original languageEnglish (US)
Article number104301
JournalThe Journal of Chemical Physics
Volume140
Issue number10
DOIs
StatePublished - Mar 14 2014

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Electron correlations
Polycyclic Aromatic Hydrocarbons
polycyclic aromatic hydrocarbons
Photons
Molecules
Geometry
photons
geometry
molecules
electrons
Crystal symmetry
atomic energy levels
symmetry
Point groups
Polyenes
Hydrocarbons
Excited states
absorption cross sections
Ground state
hydrocarbons

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Electron correlations and two-photon states in polycyclic aromatic hydrocarbon molecules : A peculiar role of geometry. / Aryanpour, Karan; Shukla, Alok; Mazumdar, Sumitendra.

In: The Journal of Chemical Physics, Vol. 140, No. 10, 104301, 14.03.2014.

Research output: Contribution to journalArticle

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