We report measurements of third-order nonlinear electric polarizabilities (hyperpolarizabilities) for ethylene, 1,3-butadiene, 1,3, 5-hexatriene and benzene molecules in the gas phase using dc electric-field induced optical second-harmonic generation. 1,2 The hyperpolarizabilities of conjugated molecules have been of interest for some time. 3-6 Because of the delocalized 7T electrons these hype...

Hyperpolarizability ratios for molecules have been measured with 0.1% accuracy, at I = 5 14.5 nm, in the gas phase as a function ofdensity. These measurements yieldy(Hz)/y(He)= 19.55kO.03, y(Ar)/y(Hz)=1.668f0.002 and y(N~)/y(Hz)= 1.283+0.001 in the zero density limit. Pair interaction contributions, determined from the density dependence of y, are larger than predicted assuming classical multip...

Binary collision-induced hyper-Rayleigh (CIHR) spectra of Kr-Xe gaseous system are computed quantum mechanically and classically within the frequency range up to 380 cm(-1). The intensities are expressed in absolute units. The details of the theory developed for the CIHR spectra are given and the properties of the profiles as well as the depolarization ratio frequency dependence are discussed. ...

In the static field limit, the vibrational hyperpolarizability consists of two contributions due to: ~1! the shift in the equilibrium geometry ~known as nuclear relaxation!, and ~2! the change in the shape of the potential energy surface ~known as curvature!. Simple finite field methods have previously been developed for evaluating these static field contributions and also for determining the e...

The Infrared spectrum of L-phenylalanine L-phenylalaninium-benzoic acid (LPB) was recorded and analyzed in the region 4000–400 cm. Optimized geometrical structures and harmonic vibrational frequencies have been computed by the B3 based (B3LYP) density functional method using 6-31+G (d, p). The calculated first hyperpolarizability is comparable with the reported value of similar structures and m...

The molecular structure of cyclohexanone was calculated by the B3LYP density functional model with 6311++G(d,p) basis set by Gaussian program. The results from natural bond orbital analysis have been analyzed in terms of the hybridization of atoms and the electronic structure of the title molecule. The formation of hydrogen bond was investigated using natural bond orbital calculation. The elect...

The interaction energy of two atoms in the presence of an external electrostatic field is evaluated up to sixth order with the help of covariant fieldtheoretical perturbation theory. The divergent Feynman diagrams entering the calculation are resummed according to a systematic procedure that has been developed in a previous paper. The pair polarizability and first hyperpolarizability that give ...

The propensity of molecules to spatially align along the polarization vector of intense, pulsed light fields is related to readily-accessible parameters (molecular polarizabilities, moment of inertia, peak intensity of the light and its pulse duration). Predictions can now be made of which molecules can be spatially aligned, and under what circumstances, upon irradiation by intense light. Accou...