Attenuated total reflectance–far ultraviolet (ATR–FUV) spectra of CH3OH, CH3OD, CD3OH and CD3OD in a liquid phase ∼Rydberg states∼

Absorption bands near 155 nm due to electronic transitions of CH3OH, CH3OD, CD3OH and CD3OD in a liquid phase were observed by using a uniquely designed attenuated total reflectance–far ultraviolet (ATR–FUV) spectrometer. Their transmittance spectra were also measured for the absorption tail region of 190–220 nm. Isotope effects were found in the peak maxima and tail structures of these bands. The ATR–FUV and transmittance spectra reveal that the lowest electronic states of CH3OH and the deuterated species in the liquid phase shift to higher energy from those in the gas phase.