Spectroscopic investigations of the X and A state dynamics of ¹³C₂H₂

The objective of the experiments described in this thesis is to perform a detailed spectroscopic study of the dynamics on the A and X state surfaces of 13C2H2 in order to further understand the acetylene - vinylidene isomerization process in the ground electronic state. Acetylene exemplifies one of the simplest bond-breaking isomerization systems and it has served as a prototype for studies of large amplitude vibrational motion in molecules. The short-time, large amplitude, vibrational dynamics of acetylene are well understood up to the acetylene - vinylidene isomerization barrier. However, direct observation of acetylene - vinylidene isomerization remains elusive. To this end, five experimental techniques, Laser Induced Fluorescence (LIF), Dispersed Fluorescence (DF), Cavity Ring-Down Spectroscopy (CRDS), Noise Immune Cavity Enhanced Optical Heterodyne Molecular Spectroscopy (NICE-OHMS) and Stimulated Emission Pumping (SEP) are employed to study the spectroscopy and dynamics of acetylene. All of these experiments focus on 13C2H2 instead of 12C2H2, except for the Cavity Ring-Down measurements. These experiments concentrate on 13C2H2 because of the possibility of observing nuclear permutation tunneling splittings which are indicative of acetylene - vinylidene isomerization. The experiments described here provide the necessary foundation for observing nuclear permutation tunneling splittings. Attempts were made to observe nuclear permutation tunneling splittings in 13C2H2 using NICE-OHMS and SEP. Although permutation splittings were not observed, these experiments enhanced our knowledge of the dynamics and spectroscopy of the A and X states of 13C2H2.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2002

Author dc:creator

• Silva, Michelle Lee, 1974-

Advisor dc:contributor.advisor

• Robert W. Field.

• Chemistry.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8360

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8360