Abstract
Inelastic processes occuring in thermal-velocity metastable atoms and molecules passing at a mean distance (1-100 nm) are investigated. These processes are caused by the quadrupolar part of the van der Waals interaction: fine-structure transitions in atoms (Ar*, Kr*), rovibrational transitions in N-2*((3)Sigma(+)(u)), transitions among magnetic sub-levels in the presence of a magnetic field. (C) 2011 Elsevier B.V. All rights reserved.