A 2-DIMENSIONAL EPR NUTATION STUDY ON EXCITED MULTIPLET STATES OF FULLERENE LINKED TO A NITROXIDE RADICAL

Photoexcited states of piro-4'-[2',2',6',6'-tetramethyl]piperidine-1'o xyl (1) were studied by the two-dimensional (2D) EPR nutation method i n toluene glass. 2D nutation spectra were observed by varying a pulse length of the first microwave pulse in the spin echo experiment, Three kinds of nutation frequencies were obtained from analyses of the 2D s pectra and assigned to those of the excited quartet and doublet states on the basis of the fictitious spin-1/2 theory. The obtained EPR para meters such as g-values, hyperfine coupling constants, and zero-field splittings were discussed in terms of the spin Hamiltonian for doubler and quartet states.