The experimental investigations devoted to the Na-D spectral line broadenin
g by molecular gases are reviewed. The theoretical interpretation of the da
ta within the framework of the classical theory of atomic spectral line bro
adening is given. The effect of adiabatic and diabatic collisions on the sh
ape of both impact and quasi-static spectral-line wings is discussed The di
fferent forms of spectral-line shape representation and the connections bet
ween them are considered. The experimental cross-sections of the Lorentzian
broadening of the Na-D lines by molecules are presented and compared with
the theoretical ones. The problem of restoration of the adiabatic interacti
on potentials from quasi-static wing profiles is noted. The C-6, C-12 param
eters of the effective atom-molecular potentials of the Lennard-Jones 12-6
form, restored on quasi-static wing profiles, are presented.