The new experimental setup for laser induced fluorescence spectroscopy (LIF) in a gas phase
was design. Electronic transitions of the linear MgC4H MgC6H and MgC4D radicals and
triangular AlC2 radical have been observed. The species were prepared in a supersonic
expansion by ablation of magnesium or aluminum rod in the presence of acetylene, diacetylene,
or methane gas. The transitions were recorded in the 415 - 475 nm region and assigned based on
previously reported mass-selective resonance enhanced ionization spectra and the rotational
structure. Astrophysical implications are briefly addressed
