Low Temperature Physics: 29, 519 (2003); https://doi.org/10.1063/1.1582334 (3 pages)
Физика Низких Температур: Том 29, Выпуск 6 (Июнь 2003), c. 695-698    ( к оглавлению , назад )

EPR spectra and rotation of CH3, CH2D, CHD2, and CD3 radicals in solid H2

Yu.A. Dmitriev and R.A. Zhitnikov

A.F. Ioffe Physico-Technical Institute, 26 Politekhnicheskaya Str, St. Petersburg 194021, Russia
E-mail: dmitriev.mares@pop.ioffe.rssi.ru

Received December 19, 2002


EPR spectra of CH3, CH2D, CHD2, and CD3 radicals have been observed in H2 matrix in the temperature range 1.6-4.2 K. The radicals were obtained by condensation on a cold substrate of two gas flows: deuterium mixed with 2 mol % methane passed through a discharge and pure hydrogen avoiding the discharge. The CD3 and CHD2 spectra were found to be a superposition of two spectra: high-temperature and low-temperature. A transformation of the shape of CD3 and CHD2 spectrum with decreasing sample temperature was observed. This is attributed to a change in the populations of the lowest rotational states of the radicals. Compared to known results for deuterated methyl radicals in Ar, the present observations suggest an existence of a hindering barrier for the radical rotation in solid H2.

32.30.-r - Atomic spectra
76.30.-v - Electron paramagnetic resonance and relaxation (see also 33.35.+r Electron resonance and relaxation in atomic and molecular physics)