2016 ◽  
Author(s):  
S. E. Braslavsky
Keyword(s):  

1982 ◽  
Vol 36 (5) ◽  
pp. 539-544 ◽  
Author(s):  
Chris W. Brown ◽  
Patricia F. Lynch ◽  
Robert J. Obremski

Artifacts appearing in infrared difference spectra can be caused by the lack of wavelength reproducibility and/or molecular interactions such as solvent effects. These artifacts appear as derivatives in difference spectra. Experimental spectra containing a number of bands with a variety of bandwidths were shifted over a range of frequencies and subtracted from the original spectra to intentionally produce anomalous bands. Models based on both Lorentzian and Gaussian band shapes were used to fit the observed data, and it was found that either band shape could be used to adequately predict the observed results within the experimental error of the measurements. Moreover, the models can be used to determine the values of the frequency shifts from the peak-to-peak differences of artifacts.


1987 ◽  
Vol 41 (1) ◽  
pp. 139-141
Author(s):  
P. Torkington

The accepted classical model for derivation of the frequency spectrum from the time-dependence of oscillator activity is considered. The exponential decay function giving rise to a Lorentzian band is modified to allow for a finite rate of growth of the oscillator, the resulting frequency spectrum is obtained, and the form normalized to unit band half-width is compared to the equivalent Lorentzian and Gaussian bands. It is shown that as the rate of oscillator growth decreases from infinity to one approximating the rate of decay, the resulting band contour changes from Lorentzian to near-Gaussian. At sufficiently fast growth-rates the band closely approximates a linear combination of Lorentzian and Gaussian.


2016 ◽  
Author(s):  
S. E. Braslavsky ◽  
K. N. Houk
Keyword(s):  

Author(s):  
Greg M. Pearl ◽  
M. C. Zerner ◽  
Anders Broo ◽  
John McKelvey

2000 ◽  
Vol 54 (2) ◽  
pp. 197-201 ◽  
Author(s):  
Michael P. Szczepanski ◽  
Augustus W. Fountain

The remote optical monitoring of gaseous contaminants is important for both military and industrial applications. An important parameter for quantifying chemical species and for predicting plume dynamics is the temperature. While in some industrial monitoring situations it may be practical to independently measure the temperature of stack emissions, for compliance monitoring and military chemical reconnaissance a remote optical means of estimating gas plume temperature is required. It was noticed that the band shape of low-resolution spectra of carbon dioxide in equilibrium with an exhaust plume was very sensitive to temperature. Spectra of carbon dioxide were acquired under controlled laboratory conditions in 5° increments from 20 to 200 °C. Various multivariate models were used to predict the temperature. It was found that partial least-squares (PLS) was unable to effectively model the simultaneous changes in amplitude and bandwidth with temperature. However, principal component regression (PCR) was found to be well correlated with temperature and allowed cross-validated prediction within 4% error.


FEBS Letters ◽  
2003 ◽  
Vol 549 (1-3) ◽  
pp. 181-181 ◽  
Author(s):  
Robert C Jennings ◽  
Flavio M. Garlaschi ◽  
Tomas Morosinotto ◽  
Enrico Engelmann ◽  
Giuseppe Zucchelli

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