Rotational temperatures have been determined from the intensities of the vacuum ultraviolet H2(2p 1 Π u →1s 1 Σ g + ) emission lines, excited by 15 keV electron impact. Their experimental values for the unperturbed 2p 1 Π d rotationallevels verify theoretical predictions, and show that the fast electron impact populates 2p 1 Π d out of the ground state byΔJ=0, analogous to the valid optical selection rule.