Cis-perp and trans-perp conformations with respect to N-O and O-O bonds were found to be the only stable ones on the BrOONO potential energy surface using the CCSD(T)//B3LYP method with the 6-311 G* basis set. The energy for the cis-perp form is 2.0 kcal mol(-1) lower than for the trans-perp form while the saddle point connecting the two minima is 9.0 kcal mol(-1) above the cis-perp level. A comparison of the relative energetics for stationary points on the BrOONO, ClOONO, and HOONO conformational potential energy surfaces is discussed. (C) 2002 Elsevier Science B.V. All rights reserved.