Lifetime millisecond range

At present time, these studies cannot be carried out, due to the short lifetimes involved, but with more intense sources of light it may be possible to reduce the measurement time enabling the measurement of 9 in the millisecond range with FTIR ellipsometry. 

Besides the emission spectrum, the lifetime of the excited state is an important feature. Many organic fluorescent molecules display very short lifetimes, in the pico- to nanosecond range, while the species of interest in this chapter (except Am(III) and Eu(II)) have rather long lifetimes, in the micro- to millisecond range. This lifetime value results from the combination of the two types of processes evoked above (radiative and non-radiative), together... 

Imbert, D., Cantuel, M., Biinzli, J.C.G, et al. (2003) Extending lifetimes of lanthanide-based near-infrared emitters (Nd, Yb) in the millisecond range through Cr(III) sensitization in discrete bimetalhc edifices. Journal of the American Chemical Society, 125, 15698-15699. 

This behavior predicts that the exchange rate between these two conformations must be much smaller than the lifetime of the states. Indeed, we found the conformational relaxation to take place in the millisecond range (50 ms) by FCS [27]. Similar behavior has been reported by Hochstraser et al. for tRNA [28],... 

A U, and for which the electronic relaxation channel is no longer available. This level, as well as all the lower levels of the ground state relax several orders of magnitude more slowly. Their lifetimes are in the millisecond range and are probably controlled by infrared radiation. 

Except for high-affinity ligands with nanomolar Ko values, lifetimes usually range in the millisecond range for most complexes. From Table 2 it can be seen that the parameters least sensitive to averaging are the chemical shifts and, to a lesser degree, Ti relaxation rates. The transferred-NOE measurements actually exploit the fast averaging of NOEs (see next section). 

The first group comprises high-resolution laser spectroscopy of short-lived radioactive isotopes with lifetimes in the millisecond range. The ions are produced by nuelear reactions induced by bombardment of a thin foil with neutrons, protons, y-quanta, or other particles inside the ion source of a mass spectrometer. They are evaporated and enter after mass selection the interaction zone of the collinear laser [466]. 

Ion-Molecule Reactions In this approach, the structure of the target ion is determined by reacting it with a neutral molecule, and the products of the reaction are compared with those that result in a similar reaction with an ion of known structure. Reactions are conducted normally in the ion cyclotron resonance cell at a low pressure (ca. 10 torr) or in a quadrupole ion trap at a moderate pressure (ca. 10 torr). Sampled ions have a lifetime in the millisecond range and thus have survived fragmentation. Because those ion-molecule reactions that are detectable in mass spectrometry are usually exothermic, the intermediate adduct is rarely observed. Therefore, the structural features of the target ion or its adduct are derived from either the fragmentation pattern or from isotope-labeling experiments. 

Another interesting application of directional energy transfer is the control of the photophysical properties of a metal ion (nd or 4f) by another one. For instance, can be used to populate the excited state of Nd or Yb . If the rate constant of the energy transfer is fast enough and if A obs(Cr) < < obs(Ln), then the excited Ln ions will decay with an apparent lifetime equal to the (long) lifetime of the 3d partner. In this case, the lifetime on Nd and Yb can be shifted in the millisecond range, which is an advantage for time-resolved detection [41, 42]. 

In homogeneous immunoassays, the analyte is biochemically coupled to two specific antibodies labeled one with a LLB and the other by an organic acceptor. Emission from the organic acceptor is detected in time-resolved mode because the population of its excited state by intramolecular transfer from the LLB shifts its lifetime in the millisecond range. In this way, it is easy to discriminate between the luminescence emitted by uncoupled and coupled antibody molecules labeled with A similarly, since the luminescence of A is spectrally different from that of the LLB, interference from Ln luminescence emitted by the uncoupled antibody labeled with the Ln chelate is also discriminated. There is, therefore, no need to wash out unused reactants. A method using FRET for the... 

In many experiments in laser spectroscopy, the interaction time of molecules with the radiation field is small compared with the spontaneous lifetimes of excited levels. Particularly for transitions between rotational-vibrational levels of molecules with spontaneous lifetimes in the millisecond range, the transit time T = df v of molecules with a mean thermal velocity v passing through a laser beam of diameter d may be smaller than the spontaneous lifetime by several orders of magnitude. 

The first group comprises high-resolution laser spectroscopy of short-lived radioactive isotopes with lifetimes in the millisecond range. The ions are... 

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