ESR investigations of spin-pair radicals in nitrogen-helium solids Conference Paper uri icon

abstract

  • We have investigated nitrogen-helium solids by X-band CW-ESR. Our samples, containing molecules and atoms of either the 14N or the 15N isotope, were produced from N2:He gas mixtures with different nitrogen impurity concentrations ranging from 0.25% to 1%. Samples were formed in a helium cryostat at 1.5 K by applying a radio-frequency discharge to a gas mixture jet that was then introduced into superfluid 4He. We achieved average concentrations of stabilized nitrogen atoms as high as 21019 atoms/cm3. We observed a strong ESR signal of stabilized nitrogen atoms at 3235 Oe. For the first time we also detected weak ESR signals corresponding to the MS = 2 transitions of 14N14N or 15N15N spin-pair radicals in nitrogen-helium solids at 1617 Oe. The intensities of these signals were 1000 or more times smaller than those of the main atomic signals. We investigated the thermal stability of the nitrogen-helium solids and observed the spin-pair radical signals in dry samples at T = 3.1 K. After explosive disintegration of the samples at 3.3 K, the spin-pair radical signal disappeared. 2006 American Institute of Physics.

name of conference

  • LOW TEMPERATURE PHYSICS: 24th International Conference on Low Temperature Physics - LT24

published proceedings

  • LOW TEMPERATURE PHYSICS, PTS A AND B

author list (cited authors)

  • Vehmanen, E., Khmelenko, V. V., Bernard, E. P., Kunttu, H., & Lee, D. M.

complete list of authors

  • Vehmanen, E||Khmelenko, VV||Bernard, EP||Kunttu, H||Lee, DM

publication date

  • January 1, 2006 11:11 AM

publisher

  • AIP  Publisher