Magnetic Field Control of the NO2Photodissociation Threshold

Abstract

This is the first experimental observation of the control of the dissociation energy of a polyatomic molecule with an external magnetic field. We have observed by laser-induced fluorescence that the N${\mathrm{O}}_{2}$ photodissociation threshold is linearly lowered by a magnetic field. This effect reaches 13.2 ${\mathrm{cm}}^{\ensuremath{-}1}$ under 14 T, i.e., $2{\ensuremath{\mu}}_{B}B$. This result demonstrates that all the rovibronic levels of N${\mathrm{O}}_{2}$ energetically above the lowest dissociation channel are significantly coupled, without any barrier, to the lowest exit channel: NO ${(}^{2}\ensuremath{\Pi}{1/2}^{}[],v\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0,J\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\frac{1}{2})$ and O ${(}^{3}{P}_{2},{M}_{J}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}2)$. This simple behavior is explained by the existence of quantum chaos within the N${\mathrm{O}}_{2}$ rovibronic levels.