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Author Choi, Sunyoung ♦ Kang, Tae Yeon ♦ Choi, Kyo-Won ♦ Han, Songhee ♦ Ahn, Doo-Sik ♦ Baek, Sun Jong ♦ Kim, Sang Kyu
Source CiteSeerX
Content type Text
File Format PDF
Subject Domain (in DDC) Computer science, information & general works ♦ Data processing & computer science
Subject Keyword Conformational Isomer ♦ Single Conformer ♦ Gauche Conformer ♦ Mati Spectrum ♦ Franck-condon Analysis ♦ Unique Structural Change ♦ Gauche-gauche Conformer ♦ Molecular Beam ♦ Conformational Preference ♦ Spectral Identification ♦ Conformer-specific Ionization Dynamic ♦ Major Conformational Isomer ♦ Conformer Specificity ♦ Occupied Molecular Orbital ♦ Spectral Simulation ♦ Ionization-driven Structural Change ♦ Specific Conformational Isomer ♦ Adiabatic Ionization Potential ♦ Vacuum Ultraviolet Mass-analyzed Threshold Ionization ♦ Trans-gauche Conformer ♦ Density Functional Theory ♦ Powerful Method
Abstract Conformational isomers of alkanethiols are isolated in the molecular beam, and the conformer-specific ionization dynamics have been investigated using vacuum ultraviolet mass-analyzed threshold ionization (MATI) spectroscopy. Only a single conformer of ethanethiol is observed to give the adiabatic ionization potential (IP) of 9.2922 ( 0.0007 eV for the gauche conformer. For isopropanethiol, IP is found to be 9.1426 ( 0.0006 for the trans conformer and 9.1559 ( 0.0006 eV for the gauche conformer. Only two major conformational isomers are identified for 1-propanethiol, giving an IP of 9.1952 ( 0.0006 for the trans-gauche conformer and 9.2008 ( 0.0006 eV for the gauche-gauche conformer. The tert-butanethiol, as expected, has a single conformer with an IP of 9.0294 ( 0.0006 eV. For 1-butanethiol, there are a number of conformers, and the assignment of the MATI bands to each conformer turns out to be nontrivial. The spectral simulation using the Franck-Condon analysis based on the density functional theory (DFT) calculations has been used for the identification of each conformational isomer in the MATI spectrum. Each conformer undergoes its unique structural change upon ionization, as revealed in the vibration resolved MATI spectrum, providing the powerful method for the spectral identification of a specific conformational isomer. The conformer specificity in the ionization-driven structural change reflects the role of the electron of the highest occupied molecular orbital (HOMO) in the conformational preference.
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Research
Education Level UG and PG ♦ Career/Technical Study