Lifetimes of electronic excited states of a molecule close to a metal surface

Abstract

We present a model for the evaluation of the metal-induced deexcitation rate for molecules close to a metal surface. In this model, the molecule is treated quantum mechanically at the density-functional theory level and its excitations with a time-dependent density-functional theory procedure. The metal is described through its dielectric response properties. The nonlocal features of such a response are taken into account by using a modified Lindhard-Mermin dielectric constant. The presence of small random roughness on the metal surface is described with the model of Rahman and Maradudin ͓Phys. Rev. B 21, 504 ͑1980͔͒. Systems in which the molecule close to the metal is immersed in an homogeneous matrix or deposited on a spacer are considered. The matrix and the spacer are treated with the polarizable continuum model. The molecule-metal and the molecule-matrix ͑or molecule-spacer͒ electrostatic interactions are described by using the integral equation formalism, numerically treated with a boundary element method. As a test case, the method has been applied to the study of phosphorescence from biacetyl close to a silver surface and immersed in or deposited on solid ammonia. Our results show that nonlocal metal response and surface roughness have an important role in explaining measured lifetimes.

Distance-Dependent Emission from Dye-Labeled Oligonucleotides on Striped Au/Ag Nanowires: Effect of Secondary Structure and Hybridization Efficiency

“…[1][2][3][4][5] Quenching occurs at distances very close to planar metal surfaces, usually ≤5-10 nm, while surface-enhanced fluorescence (SEF) generally occurs at tens of nanometers from the surface, and is sensitive to the nanoscale roughness of the metal. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Although much smaller in magnitude than the related phenomenon of surface-enhanced Raman scattering (SERS), SEF has been shown to provide up to ~10-fold increases in emission, which could be analytically important in detection strategies. [1][2][3][4][5][17][18][19][20] Predicting the optimal separation for a given experiment with precision can be difficult, as it varies with the identity and curvature of the metallic surface.…”

“…[1][2][3][4][5][17][18][19][20] Predicting the optimal separation for a given experiment with precision can be difficult, as it varies with the identity and curvature of the metallic surface. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] The behavior of fluorescent dyes on or near metal surfaces is becoming increasingly important for biosensing applications, where fluorescence is used to indicate the occurrence of specific binding events. 3,5 Bioassays can take advantage of fluorescence enhancement, quenching, or both.…”

On the description of the environment polarization response to electronic transitions

“…For instance, real‐time approaches, recently developed in the context of polarizable models, have not been treated in this scene, but represent a further important challenge in the modeling of nonequilibrium effects in ultrafast processes. Moreover, extensions of the continuum model to describe metal nanoparticles have also been developed and successfully implemented also in excitonic schemes . Their couplings with an SS approach has not been treated to date, even if it is of fundamental importance, and we expect to see it developed in the near future.…”

Quantum Optics in Nanostructures

“…A large number of works have been published on the study of spontaneous emission of QEs near NPs of specific geometries, such as spherical [ 90 , 91 ] and infinite circular ideally conducting cylinders [ 92 , 93 , 94 , 95 , 96 ]. In [ 71 ], simple asymptotics were obtained for an atom located on the surface (radial orientation) of a dielectric cylinder with dimensions smaller than the wavelength.…”