NLO properties and spectroscopic characterization of Y-shaped polymer
using quantum chemical approach
Abstract
The present study reports nonlinear optical properties such as first and
second hyper polarizabilities (β and γ) of Y-shaped polymer (P1) and
substituted polymers. The basic Y-shaped polymer (R=R1=H) named as P1.
Upon substitution of one OCH3 group in ortho position of Oxygen becomes
polymer P2 (R1=H, R=OCH3) and two OCH3 group as P3 (R1=R=OCH3). We have
also reported structural parameters, vibrational and electronic
absorption spectra of polymer and substituted using quantum chemical
methods. The geometrical parameters such as dipole moment, bond length
and angles are reported at B3LYP/6-311++g** level of theory. In
addition, the vibrational, electronic absorption spectra and NLO
properties are also reported at the same level of theory. There is
significant change in dipole moment and energy observed whereas
symmetry, bond length and angles are resembling in Y-shaped and
substituted polymer. The vibrational spectra of Y-shaped polymer (P1)
having the intense peak is C-H stretching mode observed at 1258 cm-1.
These Theoretical vibrational modes are well matching with available
experimental determinations. The method dependent and the along the X, Y
and Z-direction hyperpolarizabilites also reported. This study confirms
the polymer P1 and P2 showing first and second hyperpolarizability
response whereas P3 do not show. The electronic absorption spectra for
polymer and substituted polymers are also reported at the same level of
theory using (TDDFT) approach. The wavelength of electronic transition,
oscillator strength and HOMO-LUMO gap also reported.