- B.S. 1963, Massachusetts Institute of Technology
- Ph.D., 1967, Rice University
- Postdoctoral Fellow, 1967, Yale University
- Postdoctoral Fellow, 1967-1969, University of Colorado
Areas of Specialization
Molecular Reaction Dynamics
Physical chemistry: rates and mechanisms of gas-phase ion-molecule reactions, molecular beams, mass spectrometry, ion-molecule reactions.
Professor Hierl's research involves fundamental studies of the chemical and physical processes which occur in bimolecular, gas-phase collisions between ions and neutral molecules.
One experimental approach Professor Hierl has taken utilizes beam techniques to measure the intensities, angular distributions and velocity distributions of reactively scattered products. These studies provide detailed information on reaction probability, reaction mechanism and product final state distributions as functions of the reactants' initial translational energy.
A second experimental approach, carried out in collaboration with colleagues in the Air Force Geophysics Laboratory, uses flow tube techniques to study the effects of temperature and reactant solvation upon the rate constants and product distributions of gas-phase ion-molecule reactions such as nucleophilic-substitution, proton transfer and solvent switching.
Professor Hierl and his students are also engaged in theoretical calculations of the rate constants as functions of temperature for these reactions. These studies involve both quantum-mechanical calculations of transition state properties and statistical calculations of reaction rates.
The results of these studies provide valuable information for the evaluation of modern theories of chemical kinetics, and enable one to better understand the complex chemical behavior occurring in flames, explosions, upper-atmosphere phenomena, radiation chemistry and chemical lasers.
Rate Coefficients for the Endothermic Reactions C+ (2P) + HS(D2) ---> CH+(CD+) + H(D) as Functions of Temperature from 400-1300K, P.M. Hierl, R.A. Morris, and A.A. Viggiano, J. Chem. Phys., 106, 10145 (1997).
Rate Constants for the Reactions of N+ and N2+ with O2 as a Function of Temperature (300-1800K), I. Dotman, P.M. Hierl, R.A. Morris, and A.A. Viggiano, Int. J. Mass Spectro. Ion Processes, 167, 223 (1997).
Rate Constants for the Reactions of O+ and N2 and O2, as a Function of Temperature (300-1800K), P.M. Hierl, I. Dotan, J.V. Seeley, J.M. Van Doren, R.A. Morris, and A.A. Viggiano, J. Chem. Phys. 106, 3540 (1997).
Temperature Dependences of the Rate Constants and Branching Ratios for the Reactions of OH-(H2O)0-4 + CH3BR, A.A. Viggiano, S.T. Arnold, R.A. Morris, A.F. Ahrens, and P.M. Hierl, J. Phys. Chem. 100, 14397 (1996).
Translational Energy Dependence of Cross Sections for the Reactions of OH-(H2O)n with CH3Cl, P.M. Hierl, M.J. Henchman, and J.F.Paulson, J. Phys. Chem. 99, 15655 (1995).
Threshold Energies for the Reactions OH+CH3X--->CH3OH + X- (X=Cl, Br) Measured by Tandem Mass Spectrometry: Deprotonation Energies (Acidities) and CH3Cl and CH3BR, P.M. Hierl, M.J. Henchman, and J.F. Paulson, Int. J. Mass Spectrom. Ion Processes, 1992, 117, 475.