Energy-level crossing of atomic hydrogen spin states

Abstract

Atomic hydrogen 1H0 has four spin states. It is not well known that the upper two, in its electronic ground state, cross at a sufficiently high externally applied magnetic field Bx (ca. 17 T). The magnetic resonance spectra show particular effects in the crossing region. In the present work, we predict the relevant field-swept spectra at selected fixed frequencies, for 1H0 encapsulated in crystalline alpha-quartz powder, using the known spin Hamiltonian parameters derived from single-crystal EPR measurements. It was found that there is a 5 GHz frequency region in which spectral effects from the crossing can be observed.