The (A) over tilde-(X) over tilde electronic transition of C-3-Ar, near 405 nm, has been studied by both laser-induced fluorescence and wavelength-resolved emission techniques. Emission spectra have been recorded from 14 vibrational levels of the (A) over tilde state of C-3-Ar; these spectra consist of progressions in the ground state v(2) and v(4) vibrations (the in- and out-of-plane C-3-bending motions, respectively). With increasing bending excitation, these ground state levels shift progressively downwards compared to those of free C-3, indicating that the van der Waals complexes are becoming more tightly bound. The level structure of the two vibrations of C-3-Ar has been fitted to a perturbed harmonic oscillator model, where the potential function has the form V=V(1)r cos theta+V(2)r(2) cos 2theta (r is the amplitude of the C-3-bending motion and theta gives the orientation of the rare gas atom relative to the plane of the bent C-3 molecule). Ab initio calculations have been carried out for C-3-Ar at the coupled-cluster singles, doubles (and triples)/correlation consistent polarization valence quadruple-zeta level. They predict that the C-3-Ar complex is nearly T shaped at equilibrium, and that as the C-3 molecule bends away from the linear configuration, the preferred orientation is "arrow" shaped. From the results of the best fit to the model and the emission spectral intensities, the relative orientation of the out-of-plane pi electron of the (A) over tilde -state complex and the Ar atom has been estimated. No bands of the Ar complex were found near the C-3, (A) over tilde-(X) over tilde, (0,0) band, consistent with the fact that the (A) over tilde (1)Pi(u), v=0 level of free C-3 is strongly perturbed by triplet levels. In the excitation spectra of the Ar complex, the bands with v(b)'>0 show redshifts of about 16-36 cm(-1) compared to those of free C-3, indicating that the (A) over tilde -state complex in these levels is more tightly bonded than the (X) over tilde -state complex. (C) 2004 American Institute of Physics.