Observation of vibration-dependent electron anisotropy in O2- photodetachment

Photoelectron angular distributions (PADs) recorded for the O2(X 3Σg-) ← O2-(X 2Πg) band show significant vibrational dependence. Experimental evidence of vibrational influence on the PAD has, to date, been sparse. Consequently, little attention has been paid to vibrational effects in the consideration of direct detachment processes by recent theoretical treatments. The results presented here demonstrate the sensitivity of the PAD to vibronic coupling in the anion ground electronic state, a phenomenon which is usually neglected in direct molecular anion photodetachment. These results provide the essential data for the evaluation and refinement of existing theoretical models.