Linear and nonlinear optical properties of organic crystals: MBANP and its derivatives

Abstract

In addition to possessing strong optical nonlinearity, the (-)-2-(a-methylbenzylamino)-5-nitropyridine (MBANP) crystal has been shown to have unusual linear optical properties. Two methyl derivatives of MBANP have now been synthesized and grown as large single crystals; their refractive indices have been measured as a function of frequency and second-harmonic generation, induding the determination of the phase matching loci has been investigated. Data is also available on the racemic form of crystalline MBANP. The properties of this family of crystals have been reviewed and an attempt is made to relate the experimental responses of the crystals to their molecular structure and the calculated properties of the molecules.

QTAIM-Based Scheme for Describing the Linear and Nonlinear Optical Susceptibilities of Molecular Crystals Composed of Molecules with Complex Shapes

“…The experimental 38 and calculated linear and nonlinear electric properties of the NMMBANP crystal are summarized in Table 8, while the dispersion of refractive indices obtained from MP2 properties are shown in Figure 11. Similarly to the other crystals, the Q-LFT linear susceptibilities and refractive indices are systematically smaller than those obtained with the LFT scheme.…”

“…36,37 Therefore, a more elaborate scheme is proposed here, which enables to describe the susceptibilities of crystals built of molecules of complex shape, like (S)-2-(α-methylbenzylamino)-5-nitropyridine (MBANP) and its derivatives (Scheme 1). 38 These crystals are chosen because they have been shown…”

“…Indeed, in our previous studies, in order to describe the screening of the external electric field by the crystal environment, i.e., to evaluate the local field experienced by the NLO-phores in the crystal, the polarizability tensor of the molecule or ion is distributed equally on all the non-hydrogen atoms, − which is an approach very close to the use of the Lorentz tensors averaged over the heavy atom sites. , Therefore, a more elaborate scheme is proposed here, which enables to describe the susceptibilities of crystals built of molecules of complex shape, like ( S )-2-(α-methylbenzylamino)-5-nitropyridine (MBANP) and its derivatives (Scheme ). These crystals are chosen because they have been shown to be NLO material candidates, − while their NLO responses depend on the presence of one enantiomer or both in a racemate. Indeed, the MBANP compound crystallizes in monoclinic system ( P 2 1 space group) as pure enantiomer and in orthorhombic ( A ba2 space group) as racemate, and these two forms have very different χ (2) responses.…”

“…Indeed, the MBANP compound crystallizes in monoclinic system ( P 2 1 space group) as pure enantiomer and in orthorhombic ( A ba2 space group) as racemate, and these two forms have very different χ (2) responses. Two similar compounds are also included: 3-methyl and N -methyl MBANP derivatives, further called 3MMBANP and NMMBANP, respectively.…”

Hyper-Rayleigh scattering as a means of monitoring crystal nucleation in solution

“…7 In the present study, two molecular species have been selected because of their known large v (2) effects in the crystalline solid state. [8][9][10][11][12][13][14][15] HRS is a colligative property and, at a given incident laser power, should increase linearly in intensity with the concentration of the solute. If the HRS intensity should decrease as solute concentration increases, this would indicate either a reduction in the number of scattering centres or a reduction in the scattering power of these centres or both.…”