title: Theoretical study of electronically excited radical cations of naphthalene and anthracene as archetypal models for astrophysical observations. Part I. Static aspects.
abstract: Motivated by the recent discovery of new diffuse interstellar bands and results from laboratory experiments, ab initio quantum chemistry calculations are carried out for the lowest six electronic states of naphthalene and anthracene radical cations. The calculated adiabatic electronic energies are utilized to construct suitable diabatic electronic Hamiltonians in order to perform nuclear dynamics studies in Part II. Complex entanglement of the electronic states is established for both the radical cations and the coupling surfaces among them are also derived in accordance with the symmetry selection rules. Critical examination of the coupling parameters of the Hamiltonian suggests that 29 (out of 48) and 31 (out of 66) vibrational modes are relevant in the nuclear dynamics in the six lowest electronic states of naphthalene and anthracene radical cations, respectively.
authors.affiliation: School of Chemistry, University of Hyderabad, Hyderabad 500 046, India.
authors.forename: S
authors.initials: S
authors.lastname: Ghanta
authors.forename: V Sivaranjana
authors.initials: VS
authors.lastname: Reddy
authors.forename: S
authors.initials: S
authors.lastname: Mahapatra
mesh_terms: D000873:Anthracenes / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D004583:Electrons; D005609:Free Radicals / Q000737:chemistry; D009281:Naphthalenes / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D000873:Anthracenes; D002412:Cations; D005609:Free Radicals; D009281:Naphthalenes; C031721:naphthalene; C034020:anthracene