We have performed measurements of energy-angle distributions for low energy (E ≲ 10 keV) hydrogen ions transmitted through thin amorphous carbon foils. The applicability of standard potentials for the description of the multiple scattering is tested by making comparisons of the experimental results with theoretical calculations using the model of Sigmund and Winterbon on a broad angular scale. The angular dependence of the energy loss for protons and deuterons is analyzed using the three-components model of Fama et al., that separately considers the contribution of elastic and inelastic mechanisms and the roughness effect. Additionally, the velocity dependence of the stopping power and the possible existence of isotopic and molecular effects in the energy loss is investigated by measurements with H+, D+, \hbox{${\rm H}_2^+$}H2+ and \hbox{${\rm D}_2^+$}D2+ beams of velocities between 0.15 and 0.6 a.u.