Consider the adsorption of CO on Ni$(100).$ Given that the parameters for diffusion are D$0=5$x$10^-12$ cm$^2$ s$^-1$ and the energy of diffusion is $20\mathrm{.}5$ kJ mol$^-1,$ the desorption rate is $1012$ s$1$and energy of desorption $=110$ kJ mol$^-1($first order$).$ Find the average diffusion length for CO molecule across the surface at T $=480$ K$.$