Hi please, can you tell me what`s the meaning of 0 0.9 6 in plotrho file and how can I change it for different atoms. Thanks si.rho.dat si.rho.ps n 0 0.09 6 Ihsan ____________________________________________________________________________________ Don't pick lemons. See all the new 2007 cars at Yahoo! Autos. http://autos.yahoo.com/new_cars.html