EMISSION-SPECTRA OF ALKYL SUBSTITUTED DIACETYLENE RADICAL CATIONS - CH3-C=C-C=C-R+ WITH R=H, D, CH3, AND CD3 - CD3-C=C-C=C-R+ WITH R=H, D, CD3 - AND C2H5-C=C-C=C-R+ WITH R=H AND C2H5 - COMPETITION OF THE RADIATIVE A(PI-1)-]X(PI-1) AND FRAGMENTATION DECAY OF THEIR A(PI-1) STATES