Optics UV-visible

A.C. Quinn, P.J. Gemperline, B. Baker, M. Zhn, D.S. Walker, Eibre-optic UV/visible composition monitoring for process control of batch reactions, Chemom. Intell. Lab. Sysl, 45, 199-214 (1999). 

See also Atomic Absorption, Methods and Instrumentation Light Sources and Optics UV-Visible Absorption and Fiuorescence Spectrometers. 

Optical Properties and Radiation Effects. Within the range of wavelengths measured (uv, visible, and near-ir radiation), Teflon PFA fluorocarbon film transmits slightly less energy than FEP film (29) (Table 6). In thin sections, the resin is colorless and transparent in thicker sections, it becomes translucent. It is highly transparent to it radiation uv absorption is low in thin sections. Weather-O-Meter tests indicate unlimited outdoor life. 

Optical filters for UV, visible, or IR domains and specific wavelengths can be constructed in a similar way. 

Fig.1 A modern analytical nltracentrifuge. a Beckman Optima XLA/I, with full on-line data captnre and analysis facility, b Its UV/visible monochromator and, for interference optics, the laser light sonrce are contained in the rotor chamber and have to be installed and removed at the start/end of each rnn...

Techniques other than UV-visible spectroscopy have been used in matrix-isolation studies of Ag see, for example, some early ESR studies by Kasai and McLeod 56). The fluorescence spectra of Ag atoms isolated in noble-gas matrices have been recorded (76,147), and found to show large Stokes shifts when optically excited via a Si j — atomic transition which is threefold split in the matrix by spin-orbit and vibronic interactions. The large Stokes shifts may be explained in terms of an excited state silver atom-matrix cage complex in this... 

The copper system appears to behave similarly to the silver system, and it may be used here in order to illustrate the idea of "selective, naked-cluster cryophotochemistry 150,151). A typical series of optical-spectral traces that illustrate these effects for Cu atoms is given in Fig. 15, which shows the absorptions of isolated Cu atoms in the presence of small proportions of Cu2, and traces of Cus molecules. Under these concentration conditions, the outcome of 300-nm, narrow-band photoexcitation of atomic Cu is photoaggregation up to the Cus stage. The growth-decay behavior of the various cluster-absorptions allows unequivocal pinpointing of UV-visible, electronic transitions associated with Cuj and Cus 150). With the distribution of Cui,2,3 shown in Fig. 15, 370-nm, narrow-band excitation of Cu2 can be considered. Immediately apparent from these optical spectra is the growth (—10%) of the Cu atomic-resonance lines. Noticeable also is the concomitant... 

The optical absorption spectra of sulfonyl radicals have been measured by using modulation spectroscopy s, flash photolysis and pulse radiolysis s techniques. These spectra show broad absorption bands in the 280-600 nm region, with well-defined maxima at ca. 340 nm. All the available data are summarized in Table 3. Multiple Scattering X, calculations s successfully reproduce the experimental UV-visible spectra of MeSO 2 and PhSO 2 radicals, indicating that the most important transition observed in this region is due to transfer of electrons from the lone pair orbitals of the oxygen atoms to... 

The same reaction sequence was monitored by uv-visible spectroscopy and despite the lack of optical data for the zerovalent binary iron-isocyanide complexes, comparison with the spectrum for FeCCO) (18) reveals a close similarity. After the photolysis the original spectrum [an intense absorption at 232 nm with two shoulders at 297 and 340 nm] had decayed to be replaced by a new spectrum consisting of two bands at 220 and 382 nm. 

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