Abstract
The electronic state of Rhodamime B being hold on potassium chloride microcrystal (Rh B/KCl) is studied by means of the photoacoustic spectroscopy (PAS). A photoacoustic spectrum of the dried sample shows the prominent absorption maximum which is shifted to the longer wavelength side than the reported location of that in aqueous solution. This shift is elucidated by the instability of the ground state of dye molecules. It is suggested that this instability is introduced through the molecular deformation which is caused by the strong Coulombic interaction between Rh B zwitterions and the KCl crystal lattice. The signal height at the maximum decreases as a result of the absorption of airborn water. This is supposed to be caused by the lactone ring formation in a part of dye molecules.
