radiationless transition

A transition between two states of a system without photon emission or absorption.
See also: radiative transition
PAC, 1996, 68, 2223 (Glossary of terms used in photochemistry (IUPAC Recommendations 1996)) on page 2269
Orange Book, p. 185
See also:
PAC, 1984, 56, 231 (Nomenclature, symbols, units and their usage in spectrochemical analysis-Part VI: molecular luminescence spectroscopy) on page 234