Abstract: Lasing can be achieved by pumping a laser cell containing a vapor formed predominantly of Group VI dimers such as S.sub.2, Te.sub.2, Se.sub.2, TeO, TeSe, TeS and SeS, from a ground electronic state to a selected vibrational-rotational level in a selected excited electronic state. The selected excited electronic state is one having allowed transitions relative to the ground electronic state and the selected level of the excited state is one that is below the dissociation limit of that state. Lasing transitions then occur between the selected excited state level and higher vibrational-rotational levels of the ground state. For example, lasing is achieved at S.sub.2 (B-X) and at Te.sub.2 (A-X).