On the e. p. r. spectrum of vibrationally excited hydroxyl radicals

Abstract

Recent results by Clough, Curran & Thrush (1971) have suggested that Van Vleck’s concept of 'pure precession’ breaks down in the X²II_3/2 state of OH, and in order to explain the gas phase e. p. r. spectrum interactions with several states have to be included. In their work, they have assumed that the off-diagonal matrix elements of B are proportional to overlap between the vibrational wavefunctions of the interacting states. Results from R. K. R. curves suggest that this is not the case. Using theoretical wavefunctions, we calculate ∧-doubling constants and ∆g_J factors for the v" = 0 to 4 levels of the X²II_3/2. state assuming interaction with A²Ʃ⁺ alone. Agreement with experiment is found to be good and it is concluded that pure precession does hold for this molecule.