Knowledge Bank

Hydrogen and deuterium atoms are stabilized in xenon matrix from the gas phase and investigated by $ESR1$. It is shown that being deposited from the gas discharge in a mixture of $H2$ and Da with xenon, H and D atoms are trapped in the substitutional position of the matrix crystal lattice. ESR linewidths of H and D show an isotope effect, that is $(\Delta H)H/(\Delta H)D=1.10(4)$, where $(\Delta H)H$ and $(\Delta H)D$ are the peak-to-peak linewidths for H and D atoms, respectively. The shape of the ESR lines observed is close to Gaussian. The linewidths are found to be greatly increased by the zero-point vibrations of the atoms, the dynamical broadening being nearly equal to the static one. We show that substitutional H and D atoms trapped in solid xenon perform measurably anharmonic vibrations, and the spherically symmetric potential well which is to model the actual one for the substitutional hydrogen atom has a rather flat bottom. The coefficient $\nu (r)=\gamma exp(-\eta r)$ (where $\gamma$ and $\eta$ are constants) of the transfer of the electronic charge from Xe atom to H atom in Xe-H ``molecule” is estimated using the experimental data, r being the interatomic distance, $\gamma =25.71,\eta -1.25$, in atomic units. A comparison is carried out between experimental and theoretical values for the relative matrix shirt of the trapped H atom hyperfine (hr) structure constant, and it is found that experimental and theoretical quantities are in satisfactory agreement: $(\Delta A/Af)exp.=-1.05$theof. == -0.98% where $\Delta = A - $Ar, and Ar is the hf constant of the free atom.