the nali 1/sup 1/ sigma /sup +/(x) electronic ground state has been studied by fourier transform spectroscopy and laser-induced fluorescence up to near the dissociation limit. the fluorescence has been induced by ar/sup +/, kr/sup +/ and dye (dcm and rhodamine 6g) laser lines. fluorescence spectra have been observed up to nu ''=43 and accurate molecular constants have been calculated for the electronic ground state after reducing the wave numbers of 6417 assigned lines in a least-squares fit. with the molecular constants an inverted-perturbation-approach potential curve has been calculated. a value for the dissociation energy of d/sub e/=7105.5+or-1.0 cm/sup -1/ has been obtained by fitting the energy levels with high vibrational quantum numbers to a multipolar expansion in the inverse power of the internuclear distance. the multipolar expansion coefficients c/sub 6/, c/sub 8/, and c/sub 10/ have been obtained, showing a good agreement with theoretical values calculated earlier. in the fluorescence spectrum induced by the 476.5 nm ar/sup +/ laser line, extra fluorescence series have been observed. the possible collisional energy transfer in the 1/sup 1/ pi (b) electronic state at the origin of these lines is discussed