The main focus of this study is to determine the static and frequency-dependent electronic �� and �� values of the series of the DMN isomers, aiming to explore the effects of the position of the CH3 groups on these electric properties, potentially helpful selleck chemical Pacritinib for the isomeric discrimination. The electronic (hyper)polarizabilities, are commonly predicted by means of ab initio and/or Density Functional Theory (DFT) computations. However, as well-known in the literature for an accurate determination of the electronic (hyper)polarizabilities, the choice of the functional is critical, especially in the case of ��-conjugated compounds [33]. In fact, on the whole, the conventional DFT methods tend to systematically overestimate the electronic (hyper)polarizabilities obtained by high-level correlated ab initio levels.
On the other hand, the long-range corrected DFT methods incorporating nonlocal effects [34, 35], describe adequately the diffuse regions of the charge distributions, giving much more satisfactory performances for the prediction of the response electric properties. In the present study we used the Coulomb-attenuating hybrid exchange-correlation functional (CAM-B3LYP) [36], which has been recently employed with success for computing electronic (hyper)polarizabilities of organic compounds [37�C48].2. Computational DetailsAll calculations were performed with the Gaussian 09 program [49]. We used the molecular geometries previously optimized at the DFT-B3LYP level with the 6-31G* basis set [14].
Static and frequency-dependent electronic (hyper)polarizability tensor components ��ij and ��ijj(i, j = x, y, z) were obtained through the Coupled-Perturbed Hartree-Fock procedure [50, 51] using the DFT-CAM-B3LYP method with the polarized and diffuse 6-31+G*basis set. The CAM-B3LYP functional and the 6-31+G*basis set can be considered suitable choices especially for the prediction of the electronic (hyper)polarizabilities of organic molecules [37�C48, 52�C54]. However, we checked the performances of the basis set (6-31+G*versus POL Sadlej’s basis set [55]) and level of calculation (CAM-B3LYP versus second-order M?ller-Plesset perturbation theory (MP2)) on the related compound toluene. Dynamic (hyper)polarizabilities were evaluated at the experimental Nd:YAG laser wavelength of 1064nm (�� = 0.04282a.u.) for the SHG [��(?2��; ��, ��)] and EOPE [��(?��; ��, 0)] NLO processes.
We report the dipole moments (��), the isotropically averaged polarizabilities (��), the polarizability anisotropies (����), and the isotropically first-order hyperpolarizabilities (��vec ), which are defined, respectively, as +?6(��xy2+��xz2+��yz2)]}1/2,��vec?=��x2+��y2+��z2,(1)where????[56]��=��x2+��y2+��z2,?��?=13(��xx+��yy+��zz),����={12[(��xx?��yy)2+(��xx?��zz)2+(��yy?��zz)2 ��i(i = x, y, z) is given by ��i = (1/3)��j=x,y,z(��ijj + ��jij + ��jji).3. GSK-3 Results and Discussion3.1.