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We have developed an explicit model to explain the radiative recombination in noble metals, arising from transitions between electrons in the spconduction band and holes in the d-band generated by optical excitation. We find that the observed photon distribution has its shape from two competing factors. The first is due to the optics and the final density of states for the exiting photons. This is off-set by a d-band density of states factor increasing as the number of available d-states increase. We give a satisfactory account of the observed spectrum, using constant matrix elements, and find that luminescence can be used as a complementary tool to the ordinary elastic light scattering, giving detailed information about occupied and unoccupied states, provided the elastic optical constants are measured on the same sample.

We calculate the time-dependent nonequilibrium current through a single-level quantum dot strongly coupled to a vibrational mode. The nonequilibrium real-time dynamics caused by an instantaneous coupling of the leads to the quantum dot is discussed using an approximate method. The approach, which is specially designed for the strong polaronic regime, is based on the so-called polaron tunneling approximation. Considering different initial dot occupations, we show that a common steady state is reached after times much larger than the typical electron tunneling times due to a polaron blocking effect in the dot charge. A direct comparison is made with numerically exact data, showing good agreement for the time scales accessible by the diagrammatic Monte Carlo simulation method.

We report on the absorption of electromagnetic radiation by metallic nanoparticles in the radio and far infrared frequency range, and subsequent heating of nanoparticle solutions. A recent series of papers has measured considerable radio frequency (RF) heating of gold nanoparticle solutions. In this work, we show that claims of RF heating by metallic nanoparticles are not supported by theory. We analyze several mechanisms by which nonmagnetic metallic nanoparticles can absorb low frequency radiation, including both classical and quantum effects. We conclude that none of these absorption mechanisms, nor any combination of them, can increase temperatures at the rates recently reported. A recent experiment supports this finding.

The interaction of He ϩ with a typical metal surface ͑Al or Pd͒ is described, analyzing in detail the different mechanisms that contribute to the neutralization of the projectile when backscattered from the surface. Auger and resonant neutralization processes are considered and analyzed including a detailed quantum-mechanical description of the He-metal interaction, for projectile energies between 100 eV and 3 keV. We show that the promotion of the He-1s level, due to its interaction with the metal-atom-core orbitals, is the crucial mechanism making resonant processes operative. We find, however, that resonant processes are much more important for Al than for Pd. In Al, both Auger and resonant processes are equally important for neutralization of the ion, while for Pd we find that Auger is the dominant mechanism, making the He/Pd system the ideal case for which Hagstrum's exponential law appears to be practically valid for all velocities. We also find qualitative agreement with experimental data, which we consider a satisfactory result in view of the fact that our theory is a complex ab initio calculation free of adjustable parameters.

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We develop a theory of the Auger neutralization rate of ions on solid surfaces in which the matrix elements for the transition are calculated by means of a linear combination of atomic orbitals technique. We apply the theory to the calculation of the Auger rate of He + on unreconstructed Al͑111͒, ͑100͒, and ͑110͒ surfaces, assuming He + to approach these surfaces on high symmetry positions and compare them with the results of the jellium model. Although there are substantial differences between the Auger rates calculated with both kinds of approaches, those differences tend to compensate when evaluating the integral along the ion trajectory and, consequently, are of minor influence in some physical magnitudes like the ion survival probability for perpendicular energies larger than 100 eV. We find that many atoms contribute to the Auger process and small effects of lateral corrugation are registered.

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