Spontaneous Emission with Induced Transitions Taken into Account

ALBERT ROSE

David Parker Craig, T. Thirunamachandran

The spontaneous fluorescence emission rate (the Einstein rate) from an isolated molecule A is changed by non-identical neighbours of species B, as in vapour phase mixtures, liquid solutions or solids. In this paper the underlying pairwise A–B interactions are analysed in their effect on the rate of emission by A. The effects are reported for all separation distances using non-relativistic quantum electrodynamics with full account of retardation. The Einstein rate for molecule A in isolation is taken as standard. For short A–B distances the two larger changes are due to a reduction in the transition moment after wavefunction renormalization and to the change in emission frequency, i.e., the spectral shift, usually a red shift. Other important changes include some emission by the ‘passive’ molecule B, and a change in the emission rate of A through its coupling to B, even before the change in transition moment is brought in. A novel feature is that the emission by B induced by one-photon exchange between A a...

Takasi Endo

Inna Rebane, Rein Koch

Abstract The influence of the anisotropy of the host crystal on the spontaneous emission rate of the single‐impurity molecule and thus also on the radiative line width has taken into account. The anisotropy reveals itself in the dependence of the spontaneous emission rate on the orientation of the radiative transition dipole moment in the crystal. In this paper calculations of the relative spontaneous emission rate (the spontaneous emission rate divided by the spontaneous emission rate in the case when the transition dipole moment is parallel to the optical axis) of the quadrupole transition in a uniaxial host crystal are presented in the form which is convenient for experimenters. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Michele Crance, L Armstrong

The authors study doubly resonant multiphoton ionisation induced by two laser fields. The first field produces a near-resonant multiphoton transition between the ground state g and a discrete state 0. The second field is nearly resonant with a one-photon transition between 0 and an autoionising state 1. The spontaneous emission of both excited states is taken into account. The authors discuss and compare the spectral profiles expected for ionisation probability and fluorescence from state 1 when the first step laser is scanned.

L. F. Mollenauer, J. P. Gordon