Estimating the ground-state hyperfine shifts of group-1 atoms due to long-range collisions, static electric fields, and nearby surfaces

Many interactions perturb (or shift) the hyperfine coupling in group-1 atoms between their nuclear spin and single valence electron. Previous work provided an approach to estimate this shift for non-reactive collisions with other atoms or molecules at long range, and extended it to estimate the shift from static electric fields. We further extend this approach to estimate the shift due to a nearby conductive surface, and improve all these estimates by numerically computing updated values for the characteristic energies they use. We investigate how to estimate these energies by scaling arguments, and suggest how to adapt the approach to other applications. The results are relevant to pressure shifts in vapor cells, Stark shifts, and wall shifts in nanoscale devices.