The linear Fokker-Planck equation for external charged particles slowing down in a fully ionized D-T plasma has been solved in one-dimensional plane geometry by the technique of Legendre polynomial and Fourier series expansion. The vacuum boundary condition at the plasma surface has been treated by appending to it a fictitious medium in which angular dispersion is absent. For alpha particles slowing down in a fully ionized D-T plasma the effect of the angular dispersion term on the energy deposition profiles has been estimated quantitatively and found to be small. It is found that it may be masked by errors introduced by the discretisation procedures employed in the numerical solutions of the Fokker-Planck equation.