Structure and ESR features of glycine radical in its zwitterionic form

Extensive post Hartree-Fock calculations are reported for the geometrical structure and hyperfine parameters of the carbon-centered glycine radical in its zwitterionic form. Vibrational averaging effects connected to inversion at the radical center are significant for Cα and Hα atoms. The good agreement between computed and experimental hyperfine splittings confirms the nature of one of the radicals obtained from irradiation of glycine crystals. On the other hand, the ESR spectrum obtained in aqueous solution cannot be due to the zwitterionic form.