Research topics
Interface-Selective Nonlinear Spectroscopy
The static and dynamic properties of molecules at interfaces have been attracting many scientists' attentions. It is known that interfaces have unique properties that can not be found in bulk materials. However, little is understood about those interfaces from the microscopic viewpoints. Even simple things, such as the structure or orientation of water molecules at the air/water interface were not clear 10 years ago. Among several methods that can be used for investigations of molecular properties at interfaces, even-order nonlinear spectroscopies are the most powerful and sophisticated ones. These methods are based on an even-order nonlinear susceptibility χ(2n) (n=1,2,...) and allow us to probe molecules specifically at interfaces. In our group, by developing various new techniques of the even-order nonlinear spectroscopies, we investigate structures and dynamics of molecules at interfaces. Our studies are opening up a new field of interfacial science.
Setup of Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy
Vibrational spectra of interfacial molecules can be measured with high sensitivity. It is the only one instrument that can allow one to determine structure and absolute orientation of interfacial molecules.
Vibrational spectra of interfacial water measured by Heterodyne-Detected Vibrational Sum Frequency Generation Spectroscopy
These experimental data represent hydrogen-bonding strength and "up" vs "down" alignment of interfacial water molecules.
Setup of Heterodyne-Detected Electronic Sum Frequency Generation Spectroscopy
Electronic spectra of interfacial molecules can be measured with high sensitivity. It is the only one instrument that can allow one to determine electronic structure and absolute orientation of interfacial molecules.
Electronic spectra of interfacial molecules measured by Heterodyne-Detected Electronic Sum Frequency Generation Spectroscopy
These experimental data represent local polarity and "up" vs "down" alignment of interfacial molecules.
