Expressions for the wave number dependent shear viscosity and longitud
inal viscosity are obtained using generalized hydrodynamics and Mori f
ormalism. The results obtained for shear viscosity and longitudinal vi
scosity have been used to calculate the wave number dependent bulk vis
cosity for the Lennard-Jones potential near its triple point. It has b
een found that the bulk viscosity becomes negative for wave numbers gr
eater than 0.8 angstrom-1.