The use of chirped pulse millimeter-wave spectroscopy in chemical dynamics and kinetics

.Chirped-pulse millimeter wave (CPmmW) spectroscopy is a revolutionary technique that has taken advantage of advances in electronics to give high signal to noise broadband rotational spectra in a very short period of time that provides meaningful line intensities. We have implemented this technique in the 58 - 102 GHz range to study the rotational spectra of molecules with two heavy atoms. Photolysis (at 193 nm) and pyrolysis of vinyl cyanide have produced differing HCN and HNC vibrational population distributions. The photolysis experiment does not sample a collisional regime and the resulting spectra show excited states of HCN and HNC, whereas the pyrolysis experiment, which does sample a collisional regime, results in spectra that are devoid of vibrational satellites. This indicates that the intensities of vibrational satellite transitions sample the photolysis reaction only and not post-photolysis collisional effects. Mono-deuterated vinyl cyanide was photolyzed at 193 nm, in which all HCN/HNC are produced via a four-center mechanism and all DCN/DNC are produced via a three-center mechanism. The HCN and HNC products dominate, demonstrating the greater importance of the three-center mechanism. CPmmW spectroscopy is also a valuable tool in studying unimolecular and bimolecular reactions. We have studied the unimolecular decomposition of deuterated methyl nitrite which produces DNO products and bimolecular hydrogen abstraction reaction of NO with acetaldehyde resulting in HNO products. These reactions demonstrate the potential use of nitric oxide radical as a gas-phase catalyst to perform cracking of hydrocarbons and sugars.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Chemistry.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2013

Author dc:creator

• Shaver, Rachel Glyn

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/1721.1/79274

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/79274