As a benchmark from a recently developed high-accuracy thermochemistry protocol, D0 for trans-HO3 is calculated to be 2.29 ± 0.36 kcal mol-1, only slightly deeper than the value of 2.08 kcal mol-1 obtained using the PES, and in reasonable agreement with the experimentally estimated value of 2.93 ± 0.07 kcal mol-1. 
THERM