The nu3 and nu6 infrared bands near 500 cm-1 of monoisotopic D3Si35Cl have been studied with a resolution of 3.3 x 10(-3) cm-1. More than 800 transitions of nu3 and 2600 of nu6 have been assigned and fitted to ground and excited state parameters, final sigma(Fit) = 2.93 x 10(-4) cm-1. Ground state parameters up to quartic terms have been obtained. The excited state model included l(2, 2) and l(2, -1) interactions within nu6 and Coriolis x, y resonance between nu3 and nu6, interaction parameters being determined with high significance in all cases. The band centers nuo were determined, nu3 = 538.502 cm-1 and nu6 = 491.260 cm-1. Excellent agreement of experimental parameters with those from the ab initio harmonic and anharmonic force fields is noted. The transition moment ratio, ||µ3:µ6 || = 1:0.6(1), was determined by band contour simulation. Copyright 1998 Academic Press.