Spectrum absorption/emission

Figure 6. Absorption-emission spectra of trans M[pz(A2,B2)L B = diisopropoxybenzo and A = (SR)2. The absorption spectrum is shown as the solid line and the emission spectra are shown as the dashed lines, with the emission wavelengths in parentheses. [Adapted from (50).]...

Figure 10.1. Absorption, emission spectra, and chemical structures of representative fluorescence sensors for calcium and pH. The excitation wavelength was 345 nm for Fura-2, 488 nm for Calcium Green, and 543 nm for Carboxy SNAFL-2, T = 20°C.

In some cases, the center structure can be directly observed in the low-temperature absorption/emission spectra, but laser radiation is needed to unravel the spectral... 

UV/Vis absorption and photoluminescence spectra of semiconductors 368-373 were measured in solution to assess the effect of carbonyl functionalization on the optical absorption/emission spectra and resultant optical HOMO-LUMO energy gaps (Egap) (07CM4864). 

Wavelength (of light), 60, 61f, 256 fluorochrome absorption/emission spectra, 68f, 69t, 124t from lasers, 64f, 64t Wavelength (between drops), 159, 256 White blood cells. See Leukocytes and Lymphocytes... 

For space limitation, other recent extensions of the PCM-TDDFT scheme aimed at describing other interesting photophysics phenomena of solvated molecules have not been considered. We cite here, as examples, the application of PCM-TDDFT to the study of the Excitation Energy Transfer (EET) between chromophores in different environments [48], and of absorption/emission spectra of chromophores in complex environments such as the interphase between two different media [49], All these new QM computational tools may be of support to the efforts toward an even better understanding and description of the photophysics and of the photochemistry of molecules in condensed phase and in complex environments. 

Tripp, T. B. Nadenu, J. L. Roadside Salt Pollution and the Absorption-Emission Spectra of Sodium—A General Chemistry Experiment, J. Chem. Educ. 1974, 51, 130. 

Most current interest in u.v. spectra is concerned with retinal and its cis-trans isomers. Studies at 77 K include theoretical calculations, fluorescence, and the effect of protonation on the corresponding Schiff base. The singlet-triplet absorption spectrum of all-trans-retinol has been measured. Calculations on the absorption-emission spectra of rhodopsin suggest that there is little dependence on the angular twist in the polyene chain. Pulse radiolysis has made it... 

Heimel, G., et al. 2005. Breakdown of the mirror image symmetry in the optical absorption/ emission spectra of oligo(para-phenylene)s. / Chem Phys 122 054501. 

Emission spectra (see Chapter 2.19) are not covered in detail here, although the principles are the same as they are for absorption. Emission spectra of coordination compounds are often less solvatochromic than the corresponding absorption spectra. Emission occurs from a relaxed, non-F-C, excited state. Thus, in the case of emission spectra in fluid solution the solvent will be oriented around the emitting state which, if polar, will be stabilized by polar solvents. This will lead to a red shift with increasing solvent polarity, as the ground state will not be similarly stabilized unless the dipole moment increases and does not change direction. ... 

The MCI2 (M = Ca, Sr, and Ba) crystals are ideal candidates for studies of the spectroscopic properties of Tm " ions. First, no charge-compensation defects are required after thulium ions are introduced into these hosts. Second, there is reliable experimental information about the absorption/emission spectra of these materials [2-8]. Moreover, the earth-alkaline halides are also important from an application point of view because the laser action has been achieved in CaF2 Tm [9]. The spectra of Tm " were modeled in our earlier publication [10]. 

Equations (52) and (53) facilitate an highly efficient evaluation of transient absorption/emission spectra in the spirit of the semiclassical... 

Fig. 3.5 Structure of the octahedral [Rufbpyls] ion, the corresponding energy level diagram showing the major processes and their time scales, and the absorption/emission spectra of [Ru(bpy)3](PFg)2 in hexane at r.t...

The pure rotation spectrum of an asymmetric top is very complex, and cannot be reduced to a formula giving line positions. Instead, it has to be dealt with by calculation of the appropriate upper and lower state energies (Section 7.2.2). The basic selection rule, A7 = 0, 1, applies to absorption/emission spectra, and there are other selection rules. These depend on the symmetry of the inertial ellipsoid, which is always Dan, but the orientations of the dipole moment components depend on the symmetry of the molecule itself. For the rotational Raman effect A7= 2 transitions are allowed as well. The selection rules for pure rotational spectra are described in more detail in the on-line supplement for Chapter 7. 

The oscillator strength is a dimensionless variable that represents a measurement of the intensity of a given transition and its contribution to the absorption/ emission spectra. It is defined as (here and in the following, atomic units are used) [32] ... 

Moreover, poly-2-MOEG-3-BFl and poly-2-MOEG-9-BFl showed characteristic NMR features, absorption/emission spectra, and thermoinduced depolymerization behavior very similar to those shown by poly-BFl obtained by spontaneous polymerization. 

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