ABSTRACT
H and D ............................................................................................................................ 434
II. Chemically Bound Mu States: Structural Isotope Effects of Vibrating Species ............ 435
A. Zero-Point Energy and Anharmonicity Effects ....................................................... 435
B. Isotope Effects in Vibrationally Averaged Bond Lengths and
Bond Angles............................................................................................................. 436
C. Isotope Effects in Equilibrium Conformations........................................................ 437
D. Isotope Effects in Hyperfine Interactions of Free Radicals .................................... 439
E. The Validity of the Born-Oppenheimer Approximation ....................................... 439
III. Kinetic Isotope Effects: The Competing Effects of Zero-Point
Energy and Tunneling...................................................................................................... 441
A. The Mu Reaction with Molecular Hydrogen: The Dominance
of Zero-Point Energy ............................................................................................... 441
B. Mu Addition to Benzene: Evidence of Tunneling .................................................. 442
C. Mu Addition to Dioxygen: Cross-Over of Isotope Effects ..................................... 443
D. Mu Transfer: A World Record of a Kinetic Isotope Effect .................................... 444
E. A Reaction Proceeding over a Solvent-Induced Barrier: A Dynamic
Solvent Effect ........................................................................................................... 445
IV. Mass Effect on Diffusion ................................................................................................. 446
A. Coherent and Incoherent Tunneling of Mu Diffusion in Crystals .......................... 446
B. Diffusion of Mu in Liquid Water ............................................................................ 447
V. Concluding Remarks........................................................................................................ 447
References..................................................................................................................................... 448
Most chemists are probably more familiar with H, D, and T as isotopes of hydrogen than with
muonium (Mu), the youngest member of the family. The nucleus of this light atom is a positive
muon (m
; Mu
), an elementary particle with a mass of approximately 1/9th the proton mass.
Mu ; m
