title: Quantum chemical studies, natural bond orbital analysis and thermodynamic function of 2,5-dichlorophenylisocyanate.
abstract: In this work, vibrational spectral analysis on the solid state of 2,5-dichlorophenylisocyanate have been investigated both the experimental and theoretical vibrational data indicate the presence of various functional groups within the title of molecule. The equilibrium geometry, bonding features, harmonic vibrational frequencies, infrared and Raman intensities have been calculated with the help of density functional theory methods. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis following the scaled quantum mechanical force field calculations. The first hyperpolarizability (βtot) of this noval molecular system and related properties (μ, α and Δα) are calculated using B3LYP/6-31+G(d) and B3LYP/6-311++G(d,p) method on the finite-field approach. Second order perturbation energies and electron density in the bonding and anti-bonding orbitals are discussed on the basis of NBO analysis. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule.
authors.affiliation: Department of Physics, Karpagam University, Coimbatore 641 021, India; Department of Physics, J.J. College of Arts and Science (Autonomous), Pudukkottai 622 422, India.
authors.forename: S
authors.initials: S
authors.lastname: Saravanan
authors.affiliation: Centre for Research, Department of Physics, AA Government Arts College, Musiri, Tiruchirappalli 621 211, India. Electronic address: brsbala@rediffmail.com.
authors.forename: V
authors.initials: V
authors.lastname: Balachandran
mesh_terms: D054879:Halogenation; D017953:Isocyanates / Q000737:chemistry*; D008958:Models, Molecular; D011789:Quantum Theory; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D055672:Static Electricity; D013816:Thermodynamics
chemical_list: D017953:Isocyanates
keywords: HOMO–LUMO; Molecular electrostatic potential; NBO analysis and perturbation theory; Optimization geometry; Thermodynamic properties; Vibrational spectra