title: Investigation of crystal structure, vibrational characteristics and molecular conductivity of 2,3-dichloro-5,6-dicyno-p-benzoquinone.
abstract: Molecular geometries and vibrational spectra for the ground state of 2,3-dichloro-5,6-dicyno-p-benzoquinone (DDQ) and its anion (DDQ(-)) were computed using DFT method at the B3LYP level employing 6-311++G(d,p) basis set whereas for the first excited state (DDQ(∗)), these were calculated using TD-DFT at the B3LYP level employing the 6-311++G(d,p) basis set available with the Gaussian 09 package. The spectra have been experimentally investigated and the observed IR and Raman bands have been assigned to different normal modes on the basis of the calculated potential energy distributions (PEDs). XRD of single crystal has been investigated to determine molecular and crystal structures of DDQ. In order to elucidate the transfer of electrons, electronic structure and electronic absorption have been calculated with the TD-DFT method. Vibronic interaction and its role in the appearance of superconductivity in the DDQ, DDQ(-) and DDQ(∗) molecules have been investigated. The present XRD, molecular, electronic and vibronic studies indicate that mainly the ag C=O stretching and ring stretching modes participate in the charge transfer process.
authors.affiliation: Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005, India.
authors.forename: Poonam
authors.initials: P
authors.lastname: Rani
authors.affiliation: Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi 221005, India.
authors.forename: Gunjan
authors.initials: G
authors.lastname: Rajput
authors.affiliation: Laser and Spectroscopy Laboratory, Department of Physics, Banaras Hindu University, Varanasi 221005, India. Electronic address: rayadav@bhu.ac.in.
authors.forename: R A
authors.initials: RA
authors.lastname: Yadav
mesh_terms: D016227:Benzoquinones / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D016877:Oxidants / Q000737:chemistry*; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D016227:Benzoquinones; D016877:Oxidants; C000928:dichlorodicyanobenzoquinone
keywords: Charge transfer properties; IR and Raman spectrum; Vibrational spectrum; Vibronic coupling and electron–phonon coupling