Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


DawadiM_dis (final comments 1).pdf (17.94 MB)

ETD Abstract Container

Abstract Header

Spectroscopy and Dynamics of Small Molecules with Large Amplitude Motion

Dawadi, Mahesh B
http://rave.ohiolink.edu/etdc/view?acc_num=akron1404824783

Abstract Details

2014, Doctor of Philosophy, University of Akron, Chemistry.
This dissertation addresses the effect of large amplitude vibrations (LAV or LAVs) on the other small amplitude vibrations (SAVs) for investigating the vibrational dynamics on the molecular systems ranging from G6 to G12 symmetry, including methanol, methylamine, nitromethane, 2-methylmalonaldehyde (2-MMA) and 5-methyltropolone (5-MT). The study of the high-resolution infrared spectrum of methylamine (CH3NH2) in the nu11 asymmetric CH stretch region (2965-3005 cm-1) under sub-Doppler slit-jet conditions reveals that the torsion-inversion tunneling patterns are heavily impacted by perturbations and hence different both from the ground state and from the theoretical predictions. Two torsion-inversion tunneling models are reported for studying the high-barrier tunneling behavior in the methyl CH stretch vibrationally excited states of the molecules with G12 symmetry. These models predict the inverted tunneling pattern of the four tunneling states (A, B, E1 and E2 symmetries) in the asymmetric CH stretch excited states relative to the ground state. The trends in the patterns relative to tunneling rates and coupling parameters are presented and comparisons are made to the available experimental data. Additionally, a remarkable result that follows from the approximate adiabatic separation of the fast and slow vibrations in methanol is the existence of vibrational conical intersections (CIs) where the surfaces representing the two asymmetric CH stretches meet like the points of two cones touching point-to-point. The CIs occur in the slow coordinates space consisting of the torsion and the COH bend. Finally, the analysis of the high-resolution synchrotron based Fourier transform infrared (FTIR) spectrum for NO2 in-plane rock, nu7 , band of nitromethane reveals that the rotational energy pattern in the lowest torsional state ( m' = 0) of the upper vibrational state is similar relative to the vibrational ground state.
David S. Perry, Dr. (Advisor)
Mesfin Tsige, Dr. (Committee Member)
David A. Modarelli, Dr. (Committee Member)
Alper Buldum, Dr. (Committee Member)
Christopher J. Ziegler, Dr. (Committee Member)
291 p.
Chemistry
Torsion-inversion tunneling, high-resolution spectroscopy, conical intersection, seam of conical intersection, tunneling multiplet, torsion-rotation coupling

Recommended Citations

Citations

  • Dawadi, M. B. (2014). Spectroscopy and Dynamics of Small Molecules with Large Amplitude Motion [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1404824783

    APA Style (7th edition)

  • Dawadi, Mahesh. Spectroscopy and Dynamics of Small Molecules with Large Amplitude Motion. 2014. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1404824783.

    MLA Style (8th edition)

  • Dawadi, Mahesh. "Spectroscopy and Dynamics of Small Molecules with Large Amplitude Motion." Doctoral dissertation, University of Akron, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1404824783

    Chicago Manual of Style (17th edition)

akron1404824783
668
© 2014, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.