Plane wave Born approximation with Coulomb, relativistic and exchange
corrections is employed to obtain L1-, L2- and L3- subshell ionization
cross sections of several atoms due to electron and positron impacts
for projectile energy varying from the threshold of ionization to 60 t
imes the threshold energy. Photoionization cross sections for all the
three L-subshells of the atoms are also calculated using the hydrogeni
c approximation for the atomic wave functions. For L3-subshell the pre
sent cross sections due to electron impact are in good agreement with
a number of experimental data for different atoms over the entire ener
gy range investigated. For L1- and L2-subshells the present calculatio
ns yield qualitative agreement with the experimental data. The agreeme
nt between the present results and the limited experimental data for p
ositron impact is also satisfactory. The hydrogenic approximation for
the L-subshell photoionization is found to be good at small photon ene
rgies but it underestimates the cross sections at large photon energie
s.