Sign ofJHFin CHFCl2

摘要

If a nuclear spin is relaxed by two relaxation mechanisms with the same correlation time, the NMR lines may have differing relaxation rates. The fluorine nuclear spin in CHFCl2at low temperature is relaxed by dipolemdash;dipole interaction and by an anisotropy in the chemical shift. The sign of the coupling constant between fluorine and hydrogen (JHF) has been determined from the relaxation pattern.JHFturns out to be positive.