Determining electronic spectra at interfaces by electronic sum frequency generation: one- and two-photon double resonant oxazine 750 at the air/water interface.
The second-order nonlinear electronic spectra were measured for a dye oxazine 750 (OX750) adsorbed at the air/water interface using the multiplex electronic sum frequency generation (ESFG) spectroscopy recently developed by our group. The excitation-wavelength dependence of the ESFG spectrum was investigated, and a global fitting analysis was performed to separate contributions of one- and two-photon resonances. The analysis yielded linear interface electronic spectra in the one- and two-photon resonance regions, which can be directly compared to bulk absorption spectra. A two-dimensional plot of the linear interface electronic spectra is newly proposed to graphically represent all the essential information on the electronic structure of interfacial molecules. On this new analytical basis of the ESFG spectroscopy, the spectroscopic properties of OX750 at the interface are discussed.
Yamaguchi
Shoichi
S
Molecular Spectroscopy Laboratory, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Tahara
Tahei
T