Br-(H2O)(n) (n=1-6) clusters have been studied using ab initio calculations. The structures of the various Br-(H2O)(n) isomers differ considerably from those of the corresponding F-(H2O)(n) isomers for n=2 and 4-6, and especially so for n=6. The structures of the various Br-(H2O)(n) isomers are almost similar to those of the corresponding Cl-(H2O)(n) isomers for n=1-5. For n=6, the structures of the various Br-(II2O)(n) isomers differ considerably from those of the corresponding Cl-(H2O)(n) isomers. The relative stability of Br-(H2O)(n) isomers is significantly different from that of the corresponding F-(H2O)(n) isomers at 0 K. The relative stability of Br-(H2O)(n) isomers is close to that of the corresponding Cl-(H2O)(n) isomers at 0 K. The stable isomers are identified by means of comparing the calculated ionization potentials with experimental values. The charge-transfer-to-solvent energy and the OH stretching vibrational spectra are reported to facilitate future experimental work. (C) 2003 American Institute of Physics.