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We examine the classical energy-balance equation for a fluorescing system consisting of a molecule near a small, spherical metal particle capable of sustaining electromagnetic resonances and irradiated with laser light. From the energy-flow distribution in the entire system, we obtain the enhancement factor for the fluorescence emission of the adsorbed molecule. Numerical results demonstrate that the electromagnetic interactions of the molecule and the surface can be understood in terms of energy flow through the entire system and applied to investigate spectroscopic properties of adsorbates in similar systems. Absorption and emission rates of the adsorbed molecule are determined considering the energy-flow distribution and its dependence on the substrate as well as molecular parameters. Such understanding is useful in predicting spectroscopic responses of adsorbates.

A 12-year-old girl presented with a 15 × 15 cm, rapidly enlarging mass in left breast. Fine-needle aspiration cytology showed a benign proliferative breast lesion. Total excision of the mass was done preserving nipple and areola. Histopathology features were suggestive of giant fibroadenoma with benign phyllodes.

The dyna~ics of t?e UV photochemistry of HBr on LiF (001) has been studied by angleresolve? tlI~e-~f-fhght mass spectrometry in ultra-high vacuum. Single-photon P?ot?dIS~oclatton o.f adsorbed HBr at 193 nm resulted in photofragment translational energy dlstnbutlOns that dIffered from those produced in the gas-phase photolysis. Angular distributions of the fast H-atom photofragments peaked at 55 + S° to the surface normal consi~tent wit~ a preferentially oriented adsorbate geometry. The angular distribution of atomIC H obtamed from photodissociation ofHBr(ad) using polarized light indicated that a substantial.frac~ion of the H atoms collided with the surface before leaving it. Two types of photoreacttons m the adsorbed state were observed. Molecular hydrogen was formed in the photoinitiated abstraction reaction, H + HBr(ad) -.H 2 (g) + Br, and its markedly non-Boltzmann translational energy distribution was found to have less energy than would be c?nsistent with g~-phase experiments (performed elsewhere). Photoproducts from the bm~olecular rea~tton 2~X (a.d) -+ H2 + X 2 , X = CI, Br were also observed in the present study.ThIS photoreaction, WhICh dId not depend on prior photodissociation of HX(ad), is thought to proceed through electronic excitation of an HX dimer in the adsorbed state.J. Chern. Phys. 95 (2). 15

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