Measurement of molecular polarizability anisotropy via alignment-induced spatial focusing and defocusing

Abstract

We demonstrate that the polarizability anisotropy of acetylene molecule could be experimentally determined by molecular alignment induced spatial focusing and defocusing effects under femtosecond impulsive excitation. The molecular alignment signals of oxygen and acetylene were measured under identical experimental conditions and the polarizability anisotropy of acetylene was quantitatively determined with oxygen as the reference molecule. Meanwhile, the Kerr coefficients of oxygen and acetylene were estimated. This intuitive and simple method is also applicable to other molecules. PACS number(s): 33.15. Kr, 42.65.Jx, 37.10.Vz

First-Principles Calculation of Dielectric Response in Molecule-Based Materials

“…Conversely, when studying processes at the nanoscale, the polarization response of a single molecule in a specific orientation may be important in a variety of chemical and physical processes. 51,52 For example, in self-assembled molecular monolayers, where the orientations of the molecular components can be controlled, this information should be useful for designing in specific dielectric responses for a given molecular assembly. 53,54 This effect is also seen when measuring the dielectric response of crystalline materials, which may exhibit anisotropic dielectric responses depending on the direction of the applied field.…”

“…In fully disordered bulk macroscopic media this anisotropy is unimportant, since all orientations are represented and averaged in a standard dielectric measurement. Conversely, when studying processes at the nanoscale, the polarization response of a single molecule in a specific orientation may be important in a variety of chemical and physical processes. , For example, in self-assembled molecular monolayers, where the orientations of the molecular components can be controlled, this information should be useful for designing in specific dielectric responses for a given molecular assembly. , This effect is also seen when measuring the dielectric response of crystalline materials, which may exhibit anisotropic dielectric responses depending on the direction of the applied field. − Thus, the local dielectric response of a molecule is not determined solely by chemical composition, but critically influenced by the orientation of the molecule with respect to the applied electric field.…”

Scattering of adiabatically aligned molecules by nonresonant optical standing waves

“…5 (B and C), with other parameters such as a rotational temperature of predetermined samples. Such a method for measuring the polarizability anisotropy is complementary to the techniques based solely on the molecular alignment by nonresonant propagating laser fields (46)(47)(48)(49).…”

Pulse polarization evolution and control in the wake of molecular alignment inside a filament

“…For molecular alignment induced birefringence of the probe pulse, the refractive indices' modulation parallel ( align [14,15], where N and n 0 denote the molecular number density and linear refractive index of the initially randomly aligned molecules. Δα is the molecular polarizability anisotropy, θ is the angle between the pump laser's polarization and the molecular axis, < > t is the time-dependent ensemble average [7,16,17], and t is the retarded time between the pump and probe pulses. The laser-induced plasma defocusing has no preference parallel and perpendicular to the laser field, thus the resulting birefringence ( , ) align n r t Δ can be expressed as…”