Time-dependent polarization transfer from molecular rotation to nuclear spin

Abstract

It has been proposed recently that hyperfine depolarization of selected molecular rotational states can be used to produce molecules with highly polarized nuclear spins, and formulas for two distinct nuclei have been given in the limit of hierarchical approximation. Here we present the general, nonhierarchical coupling formalism for the derivation of the ${H}_{[i]}^{(k)}(I,t)$ factors that govern the time dependence of the nuclear polarizations. The described technique, especially when combined with methods that polarize the electronic angular momentum, can lead to the production of highly polarized atoms from molecular photodissociation, at densities close to that of the parent molecule. In addition, we calculate the time dependence of the H and F nuclear spin polarizations, following the pulsed-laser preparation of the HF $(v=1,J=1,m=1)$ state. It is shown that the polarization of the F and H nuclear spins attain values of about 85% and 70% at time delays of about $1\phantom{\rule{0.3em}{0ex}}\mathrm{\ensuremath{\mu}}\mathrm{s}$ and $4\phantom{\rule{0.3em}{0ex}}\mathrm{\ensuremath{\mu}}\mathrm{s}$, respectively. Similar results are shown for the pulsed preparation of the DF $(v=0,J=1,m=1)$ state, demonstrating the D atoms can also be significantly polarized.