Seminar

Conformational Structures of Small Molecules in the Gas Phase

조회수 : 229 등록일 : 2015.05.18 19:08

일시 : 2015.05.20 17:00
소속 : 경상대학교 화학과
발표자 : 최명룡
장소 : R404
The conformational structures of jet-cooled acetaminophen (AAP) were investigated by resonant 2-photon ionization (R2PI) and UV-UV hole-burning (UVHB) spectroscopy1..  Recent investigation with IR-dip spectroscopy revealed that each conformer of AAP gives two independent transitions starting from the most stable 0a1 and the hot 1e internal rotational level2.  Further spectroscopic investigation of AAP-(H2O)n (n= 0 – 2) with an aid of IR-dip spectroscopy will be presented and discussed.
Second part of the talk will be focused on the recent results of conformational structures of 3-cyanoindole-(H2O)n (n=0-2).  The excitation spectra of 3-cyanoindole (3CI) and its water clusters, 3CI-(H2O)n (n= 1 and 2), have been measured by R2PI and UVHB spectroscopy3..  The observed spectra are compared with the predictions of ab initio and density functional theory calculations.  The comparison suggests that the spectra arise from a single conformer of 3CI and two conformers of 3CI-(H2O)n (n= 1 and 2) each.  UVHB and IR-dip spectroscopy were employed to identify the conformers of 3CI-(H2O)1 and 3CI-(H2O)2.  Furthermore, R2PI and UVHB spectra were compared with the results of Franck-Condon (FC) simulations that can determine the change in a molecular geometry of 3CI-(H2O)n (n=0-2) on electronic excitation4..  It was found that the most stable structure for each 3CI-(H2O)n (n=0-2) was identified and their excited state geometries were little influenced upon excitation. The conformation-specific structural assignment of the conformers is compared and discussed with theoretical calculations.
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