  The O-D stretch fundamental region of the deuterated water dimer, (D2O)2, is
further studied using a pulsed supersonic slit jet and a tunable optical
parametric oscillator infrared source. The previously unobserved acceptor
symmetric O-D stretch fundamental vibration is detected, with Ka = 0 <-- 0 and
1 <-- 0 sub-bands at about 2669 and 2674 cm-1, respectively. Analysis indicates
that the various water dimer tunneling splittings generally decrease in the
excited vibrational state, similar to the three other previously observed O-D
stretch fundamentals. Two new (D2O)2 combination bands are observed, giving
information on intermolecular vibrations in the excited O-D stretch states. The
likely vibrational assignments for these and a previously observed combination
band are discussed.
