The effect of small cluster environment on molecular oscillator strengths and spectra

In this paper, we present an electrostatic theory of the effect of small atomic cluster environment on molecular oscillator strengths and spectra. The molecular dipole is represented by a classical oscillating charge distribution and the cluster atoms by spherical polarizable particles. From our general theoretical results, we calculate the effect of cluster size and geometry on the molecular radiative lifetime and the spectral shift. These properties exhibit a considerable sensitivity to the cluster and molecular geometry, i.e., the cluster size and structure, the molecule-atom(s) distance(s), the spatial size of the molecular transition dipole, and molecular orientation within the cluster. The reduced plot of the relative change in the oscillator strength vs the relative frequency shift seems to have universal character and is useful in analyzing and predicting experimental trends. Available experimental results are consistent with the theoretical predictions.