E. Tiesinga et al., A SPECTROSCOPIC DETERMINATION OF SCATTERING LENGTHS FOR SODIUM ATOM COLLISIONS, Journal of research of the National Institute of Standards and Technology, 101(4), 1996, pp. 505-520
We report a preliminary value for the zero magnetic field Na S-2(f = 1
, m = - 1) + Na S-2(f = 1, m = - 1) scattering length, a(1, - 1). This
parameter describes the low-energy elastic two-body processes in a di
lute gas of composite bosons and determines, to a large extent, the ma
croscopic wavefunction of a Bose condensate in a trap. Our scattering
length is obtained from photoassociative spectroscopy with samples of
uncondensed atoms. The temperature of the atoms is sufficiently low th
at contributions from the three lowest partial waves dominate the spec
trum. The observed lineshapes for the purely long-range O-g(-) molecul
ar state enable us to establish key features of the ground state scatt
ering wavefunction. The fortuitous occurrence of a p-wave node near th
e deepest point (R(e) = 72 a(0)) of the O-g(-) potential curve is inst
rumental in determining a(1, - 1) = (52 +/- 5) a(0) and a(2,2) = (85 /- 3) a(0), where the latter is for a collision of two Na S-2(f = 2, m
= 2) atoms.