Post-Doctoral 
Experience: 

Professional  
Experience: 
 

University of Pennsylvania, 1988-1989 

Lecturer, Bryn Mawr College, Bryn Mawr, PA, 1990-1991 
Assistant Professor, St. Francis College, Loretto, PA, 1991-1996 
Visiting Assistant Professor, UNC-Charlotte, 1997-1998                                                      Lecturer, UNC-Charlotte, 2000-present 

Internal rotations in isolated molecules  The motion of a molecular group, such as a methyl group, in a solid can be related to the electrostatic potential surface of the molecule or the surrounding lattice. So far, my work on methyl group rotation has concentrated on the limit of very low rotational barriers achieved by isolating C_3v molecules such as CH₃CN in rare gas matrices. The nearly free rotation of the molecule leads to a coupling between spin and rotational level populations that drastically alters the intensity and shape of the proton NMR spectrum after the temperature of the matrix is suddenly changed. Methyl proton spins become ordered with respect to at least three local fields and the separation of the respective signal components provides independent information regarding the rotational dynamics. The results have shed light on the molecule-lattice interaction such as the rotational barrier height, the proximity of molecules in the matrix, and the effect of matrix annealing. But many experimental observations are yet unexplained such as the detailed kinetics of the spin polarization process in molecules with ¹H-¹³C interactions, the description of librational motion in the case of less prolate molecules like CH₃F, and the temperature dependence of the methyl group spin-rotation coupling.

Characterization of Polymer blends  Polymer blending is a common practice for obtaining materials with improved properties, better processibility, or lower cost. However, the complexity of these systems makes it difficult to obtain accurate structure-property relationships. Solid-state NMR has provided many answers to questions of structure and dynamics in solid blends. Cross-polarization magic-angle-spinning (CP-MAS) techniques are particular useful in distinguishing dilute nuclei such as ¹³C or ²⁹Si on different polymers, different segments of the same polymer, or in different microdomains. This spectral resolution also makes it possible to measure spin relaxation rates independently so that correlation times for motions of side chains, backbone segments, etc., can be obtained. I am particularly interested in applying two-dimensional techniques that exploit the spin diffusion of abundant nuclei to determine the microhomo- or heterogeneity of polyvinyl alcohol blends and its effect on mechanical properties. 
 

"Dynamic Spin Ordering of Matrix Isolated Methyl Rotors", D. White and 
M. Murphy, in The Encyclopedia of Nuclear Magnetic Resonance, 
D. M. Grant and R. K. Harris, eds., John Wiley & Sons, Sussex, 1996. 

"NMR Studies of Methyl Group Spin-Rotation Coupling", M. Murphy and 
D. White, J. Chem. Phys. 91, 4504, 1989. 

Doctoral Dissertation: "Dynamic Polarization and Relaxation of Methyl Group Spins in Matrix Isolated Molecules" 

"Heteronuclear Dipolar Order in Methyl Rotors", M. Murphy and D. White, 
 J. Chem. Phys. 86, 1640, 1987. 

"An NMR Study of Al-Mn Quasicrystals and Related Materials", 
K. Carduner, B. Suits, J. DiVerdi, M. Murphy, D. White, J. Mater. Res. 2, 431, 1987. 

"Zeeman and Dipolar Coherences in Dilute Powders", M. Murphy, 
M. Semack, D. White, J. Mag. Res. 72, 143, 1987.