Abstract
An examination is made of reported experimental and theoretical values of the logarithmic mean excitation energy, l, for the stopping power of molecular hydrogen and of values of l determined in this work from various recent experimental values of the stopping cross-section of molecular hydrogen for α-particles and protons of various kinetic energies. Values of l for molecular hydrogen determined in this work from experimental values of the stopping cross-section reported recently by various investigators give support to a value of over 20 eV for l of molecular hydrogen that was predicted by a recent application of the local plasma model for the determination of l that took chemical binding into consideration. This value is much higher than all of the previously accepted values of l for molecular hydrogen.