Raman study of vibrational dynamics of aminopropylsilanetriol in gas phase.

Raman spectrum of aminopropylsilanetriol (APST) in gas phase has been recorded at room temperature in macro chamber utilizing two-mirror technique over the sample tube. Unlike predominantly trans molecular conformation in condensed phase, the spectra of vapor show that the molecules are solely in gauche conformation with intramolecular hydrogen bond N···HO which reduces the molecular energy in respect to trans conformation by 0.152 eV. The assignment of the molecular spectra based on the DFT calculation is presented. The strong vibrational bands at 354 cm(-1), 588 cm(-1) and 3022 cm(-1) are proposed for verifying the existence of the ring like, hydrogen bonded structure. Special attention was devoted to the high frequency region, where hydrogen bond vibrations are coupled to stretchings of amino and silanol groups.

Line focusing in micro-Raman spectroscopy.

In a microscope of a micro-Raman spectrometer a cylindrical lens is introduced to form a line-focus microprobe (LFMP). The dimensions of the LFMP are 0.66 x 167 microm. The lateral spatial resolution of Raman scattering with the LFMP is equal to the spatial resolution of the point-focus microprobe (PFMP). It is shown that the LFMP system enables measurements with a laser power density that is 320 times lower than the PFMP. For the same laser power density in both types of illumination, the LFMP Raman spectra give approximately radical320 or asymptotically equal to 18 times better signal-to-noise ratio.