The spontaneous emission decay dynamics of nanocrystal quantum dots embedded into biotemplated titania photonic crystals with a diamond-based lattice are investigated. Modification of the decay rate of quantum dot emission over wide frequency bandwidths in the visible by the photonic crystals is observed. Frequency-dependent analysis reveals both inhibition and enhancement of emission with a ra...

We calculate limits on the properties of neutrinos using data from gammaray detectors on the Pioneer Venus Orbiter and Solar Max Mission satellites. A massive neutrino decaying in flight from the supernova would produce gamma rays detectable by these instruments. The lack of such a signal allows us to constrain the mass, radiative lifetime, and branching ratio to photons of a massive neutrino s...

Efficient photoluminescence ~PL! up-conversion has been observed in colloidal CdTe quantum dots with an energy gain of as high as 360 meV. Compared with the normal PL, the peak energy of this up-converted PL ~UCPL! shows a redshift of about 80 meV, and the corresponding radiative lifetime becomes nearly twice as long. This UCPL is attributed to the carrier recombination involving surface states...

The effects of the chemical constitution and structure of the substituent on the excited state dynamics of several model fluorescent pyrene-labelled molecules of biophysical interest have been examined. Nine new 1-substituted pyrenyl compounds, Py-NH-CO-C2H5, Py-NH-CO-Leu-Boc, Py-CH2-NH-CO-C2H5, Py-CH2-NH-CO-Leu-Boc, Py-CO-NH-C3H7, Py-CO-NH-Leu-OMe, Py-CH2-CO-NH-C3H7, Py-CH2-CO-NH-Leu-OMe and P...

We compute the gluino lifetime and branching ratios in Split Supersymmetry. Using an effective–theory approach, we resum the large logarithmic corrections controlled by the strong gauge coupling and the top Yukawa coupling. We find that the resummation of the radiative corrections has a sizeable numerical impact on the gluino decay width and branching ratios. Finally, we discuss the gluino deca...

II We have developed laser sources ofsodium-resonance radiation based on the sumfrequency mixing ofNd:YAG laser radiation. The sources are suitable for generating a fluorescence spot in the earth's mesospheric sodium layer for use in adaptive optics compensation. Taking into account the sodium fluorescence lifetime, Doppler broadening, hyperfine structUre, radiative saturation, optical pumping,...

Time-correlated single photon counting methods are used with confocal microscopy and maximum likelihood estimation analysis to obtain fluorescence lifetime trajectories for single quantum dots with KHz update rates. This technique reveals that control of the solution environment can influence both radiative (k(rad)) and nonradiative (k(nonrad)) pathways for electron-hole recombination emission ...

In their paper “Design strategies to minimize the radiative efficiency of global warming molecules,” Bera et al. (1) mistakenly equate the relative magnitudes of integrated absorption within the atmospheric window (800–1,400 cm) with relative radiative efficiencies of different molecules. Radiative efficiency is defined as the change in net radiation at the tropopause caused by a given change i...

The lifetime of non-equilibrium electrons and holes in semiconductors is crucial for solar cell optoelectronic applications. Non-adiabatic molecular dynamics (NAMD) simulations based on time-dependent density functional theory (TDDFT) are widely used to study excited-state carrier dynamics. However, the calculated lifetimes often different from experimental results by orders magnitude. In this ...