Theoretical study of OH addition to α-pinene and β-pinene

Quantum chemical calculations have been employed to determine the structures and energetics of the radicals arising from the OH addition to α-pinene and β-pinene. The rate constants of OH addition to α-pinene and β-pinene are calculated using the canonical variational transition state theory (CVTST). At the B3LYP/6-31G(d,p) level of theory, the high-pressure limit rate constants at 300 K are 5.1 × 10−11 cm3 molecule−1 s−1 for α-pinene and 6.1 × 10−11 cm3 molecule−1 s−1 for β-pinene, consistent with experimental studies. These results provide the isomer-specific rate constants and branching ratios for OH addition to α-pinene and β-pinene.