Three-photon absorption and vibrational spectroscopic study of 2-methylamino-5-chlorobenzophenone

In this paper, the vibrational spectral analysis and three-photon absorption properties of an organic material of 2-methylamino-5-chlorobenzophenone have been reported. The geometry and harmonic vibrational wavenumbers are calculated with the help of B3LYP density functional theory method. The detailed interpretation of the vibrational spectra has been carried out with the aid of normal coordinate analysis following the scaled quantum mechanical force field methodology (SQM). SQM force fields have also been used to calculate potential energy distribution (PED) in order to make conspicuous vibrational assignments. The nonlinear absorption properties have been investigated in ethanol solution at 532 nm using the Z-scan technique employing laser pulses of 5 ns duration. Open aperture Z-scan data reveal the presence of effective three-photon absorption for ns pulses at 532 nm resulting in a strong optical limiting behavior, indicating possible photonic applications.

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► Vibrational spectra of the NLO material 2-methylamino-5-chlorobenzophenone have been analyzed.
► Nonlinear optical absorption of the sample has been studied by open-aperture Z-scan technique.
► The natural bond orbital (NBO) analysis has been carried out.
► The electronic absorption properties were studied.