Variation Of Radiative Lifetimes Research Articles

Radiative lifetime of multiexciton in CdSe/CdS core–shell quantum dot

The radiative lifetime of exciton, trions and biexciton in CdSe/CdS core–shell quantum dot has been calculated using effective mass approximation. The eigen-value and eigen-functions were obtained by solving Schroedinger and Poisson equations in a self-consistent iterative manner. The observed ratio of lifetimes of exciton and biexciton τ(x):τ(xx) is 2:1. The trions have a radiative lifetime similar to that of a monoexciton. Variation of radiative lifetimes with core radius and shell thickness was studied. Our investigations of Stark effect on this system point that only in the weak confinement region the external electric field has a control on the radiative lifetime.

Luminescent properties of Ce3+ ions in zinc phosphate glass prepared in air

Glasses are prepared by sintering P2O5, ZnO and Ce2(C2O4)3 · 10H2O mixtures at 1 100 °C in air and then annealed at 400 °C for 10 hours. The obtained glasses are homogeneous, transparent and colorless. Emission and excitation spectra are measured for the samples and the results show that the glasses contain Ce3+ trivalent cerium ions. The parameters of glass preparation obtained here may be adapted to preparing this type of glasses doped with other lanthanide ions, so as to study energy transfer phenomena and variation of radiative lifetime with refractive index due to local field effect.

Radiative lifetimes of excited states of atoms

A review of experimental and theoretical studies of radiative lifetimes of excited states of the hydrogen atom, of atoms of alkali metals, and atoms of the copper subgroup is presented. A complete compilation of all published values of radiative lifetimes of all excited states with a critical analysis for every atom is given. The regularities in the variation of radiative lifetimes in spectral series of excited states are brought out and constants of the power-law dependences on the effective principal quantum number are determined. A correlation between the behavior of lifetimes and the effective orbital parameter is established and it is proposed to use this correlation for the determination of the application limits of the power-law constants for evaluation of lifetimes of uninvestigated states. On the basis of a critical analysis of published sources, of the regularities in the variation of lifetimes and of a statistical treatment of values available in the literature, a table of recommended values of radiative lifetimes of excited states of all atoms of the first group is compiled.