Complete determination of ¹⁴N hyperfine and quadrupole interactions in the metastable triplet state of free-base porphin via electron spin echo envelope modulation

Abstract

Through the use of the electron spin echo envelope modulation method, we have accomplished the complete determination of the 14N hyperfine and quadrupole interaction tensors in the lowest photo-excited triplet state of free-base porphin in an n-octane single crystal at ∼1.4 K. The results give insight into the molecular structure of the porphin in the excited state, the relationship between the nitrogen spin density and observed hyperfine couplings, and the effect of hydrogen bonding interactions on the quadrupole coupling constants and principal axes. © 1984 American Institute of Physics.