ESR effects of singlet--triplet mixing in radical pairs. Determination of the individual g tensors and the exchange coupling constant from spectral shifts due to off-diagonal Zeeman terms

Journal Article · Sun May 01 00:00:00 EDT 1983 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.445469· OSTI ID:6225962

Byberg, J R; Bjerre, N; Lund, A; Samskog, P

ESR spectra of exchange-coupled radical pairs exhibit shifts in the fine structure splitting proportional to the square of the microwave frequency ..nu../sub 0/ and shifts in the hyperfine splittings proportional to ..nu../sub 0/, provided the g tensors of the members of the pairs are nonequivalent. These shifts stem from electronic Zeeman terms in the full spin Hamiltonian of the pairs, which tend to mix the singlet and triplet electron spin states. Expressions for the shifts are derived from a second order perturbation calculation based on the conventional triplet description. The results are employed to obtain the individual g tensors and the exchange coupling constant for a radical pair formed by x irradiation at 26 K of pentaerythritol crystals.

• Research Organization: Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark
• OSTI ID: 6225962
• Journal Information: J. Chem. Phys.; (United States), Vol. 78:9
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
ORGANIC COMPOUNDS
CHEMICAL RADIATION EFFECTS
RADICALS
ELECTRON SPIN RESONANCE
SPECTRAL SHIFT
X RADIATION
ZEEMAN EFFECT
CHEMISTRY
ELECTROMAGNETIC RADIATION
IONIZING RADIATIONS
MAGNETIC RESONANCE
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RESONANCE
400600* - Radiation Chemistry