CAUTERIZATION OF DIELECTRIC PROPERTIES FOR MONOLAYERATAIR-WATER INTERFACE BY MEANS OF MAXWELL DISPLACEMENT CURRENT AND OPTICAL SECOND HARMONIC GENERATION MEASURMENT

点击翻译按钮获取中文摘要

The purpose of this investigation was to characterize the linear and nonlinear dielectric properties of organic monolayer films by means of Maxwell-displacement current (MDC) and optical Second Harmonics Generation (SHG) measurement. The macroscopic dielectric properties such as linear and nonlinear dielectric constants are strongly related to the orientational order parameters of the constituent molecules. From this point of view, this investigation has been carried out on the basis of the idea of MDC measurement coupled with SHG measurement, proposed by the investigators.The investigators measured MDC and SHG signals from the monolayer on the water surface of nCB and nOCB molecules, where they constructed a new measurement system using 532 (and 1064 nm) fundamental waves to gain the high SN ratio. Using the experimental results, they clarified the relationship between MDC and photoisomerization of azo-molecules based on the quantum chemical three-state model Furthermore they analyzed the phase transition occurring in phospholipid and liquid crystal monolayers using a continuum elastic-theory. They detected this kind of phase transitions in nOCB liquid crystalline monolayer. Finally they derived the theoretical relationship between the microscopic and macroscopic nonlinear susceptibilities in C_2 symmetry.