  Angular momentum changing collisions can be suppressed in atoms whose valence
electrons are submerged beneath filled shells of higher principle quantum
number. To determine whether spin-exchange collisions are suppressed in these
"submerged shell" atoms, we measured spin-exchange collisions of six hyperfine
states of Mn at temperatures below 1 K. Although the 3d valence electrons in Mn
are submerged beneath a filled 4s orbital, we find that the spin exchange rate
coefficients are similar to those of Na and H (which are non-submerged shell
atoms).
