@unpublished{pittir9738,
           month = {January},
           title = {Reaction Volumes of Photoinitiated Reactions, and Their Use As Probes of Reactive Intermediates},
          author = {Kevin William Davies},
            year = {2009},
        keywords = {high-pressure photoacoustic calorimetry; linear alkane photoacoustic calorimetry},
             url = {http://d-scholarship-dev.library.pitt.edu/9738/},
        abstract = {Photoacoustic calorimetry is a sensitive method for measuring the enthalpies, kinetics, and changes in volumes for reactions that generate transient intermediates through photoexcitation. This work focuses on building a better understanding of {\ensuremath{\Delta}}Vrxn, to ascertain the importance of accounting for {\ensuremath{\Delta}}Vrxn when measuring enthalpies of reaction via photoacoustic methods. {\ensuremath{\Delta}}Vrxn for three metal carbonyls has been measured. The results presented herein show that to obtain high-quality thermochemical information from photoacoustic measurements, it is necessary to account for the contribution of {\ensuremath{\Delta}}Vrxn. Neither the magnitude nor the sign of this contribution may be predicted without either the direct measurement of {\ensuremath{\Delta}}Vrxn or (as an outcome of the research described in this dissertation) computationally. Failure to account for this contribution may results in errors in the measured {\ensuremath{\Delta}}Hrxn by as much as 79\% [e.g. (CH3OC)Mn(CO)5 in octane].This dissertation also lays the groundwork for the use of {\ensuremath{\Delta}}Vrxn to distinguish between possible structures of short-lived intermediates though a combination of photoacoustic measurements and computational chemistry. A protocol is described that will allow molecular dynamics simulations to be used to determine the solvated volume of a molecule, and to combine several of these measurements to allow the volume change accompanying a reaction to be determined computationally. Simulations conducted via this protocol are in good agreement with our experimental results. These simulations will allow experimental results to provide a new window into the nature of short-lived intermediates, and the mechanistic of their reactions. Several unsuccessful molecular dynamics simulations are also described in order to identify cases where simulations may not provide accurate data and how these issues may be addressed.}
}