Emission of delayed luminescence after reaction of active nitrogen with mixed aromatic polycrystals at 77 K. Evidence for an active nitrogen induced chemi-ionization

Abstract

Weak ‘delayed’ luminescence is emitted after the reaction of active nitrogen with mixed host–guest aromatic polycrystals at 77 K. A spectroscopic investigation of this delayed luminescence shows that: (i) the spectrum of the delayed luminescence agrees with the guest phosphorescence spectrum and (ii) trapped electrons are created during the initial gas–solid reaction of active nitrogen with the cold hydrocarbon surface. This active nitrogen induced chemi-ionization is suggested to occur via the two-body recombination of nitrogen atoms N(⁴S) on the cold surface. This study completes previous e.s.r. and optical investigations of the same systems during the reaction of active nitrogen.