成大物理系徽
量子資訊與理論物理中心/台南
演講題目: Investigations Of Protonated Molecule-Water Clusters By Infrared Spectroscopy/ Photodissociation Dynamics & Crossed Molecular Beam Reaction Dynamics Using Synchrotron Radiation Ionization
演講人: Dr. Chanchal Chaudhuri
新竹同步輻射中心
演講時間: 2006 年 6 月 20 日
星期二  上午 10 : 00
演講地點: 物理二館二樓49223
內容摘要:  
Protonated molecule-water clusters [H+(Mm(H2O)n), M=momecule] have been characterized by vibrational predissociation infrared spectroscopy and ab initio calculations at varying stages of hydration in the gas phase produced by corona discharge supersonic expansion. Isomeric structures, including both H3O+- and H+M-centered forms, were identified from the hydrogen-bonded and non-hydrogen-bonded NH and OH stretching spectra of the species. Interesting features such as O-protonation, grouping of H2O and proton pulling effect have been observed in H+[HC(O)NH2(H2O)n]. Proton transfer dynamics is illustrated.
Investigating the photodissociation of Acrolein [H2C=CH{CHO] at 193 nm (148 kcal/mol) by photofragmentation translational spectroscopy coupled with synchrotron radiation ionization of the photoproducts, five primary channels have been observed. The anisotropy parameters (-values) of the all the photoproducts were found to be nearly zero. The measurement shows that IP of -CH2CHCO radical is ~7 eV. The evidence of the secondary dissociation C2H3彪2H2+H from the slow part was found. The photodisociation dynamical pathways on the potential surfaces have been focused.
The reaction O+SiH4 has been investigated employing a crossed molecular beam apparatus coupled with synchrotron radiation ionization (SRI) and time-of-flight (TOF) mass spectrometric detection at Ecoll ~6.7 kcal/mol. The O atoms in the beam produced by high voltage pulsed-discharge were mainly populated in the 3P state (3P:1D = 95:5). We have identified major reaction channels. The measured ionization potential of SiO ~11.2 eV is in good agreement with calculation. Relative branching ratios of the product channels have been determined and the Dynamics of the observed reaction channels are addressed.