Gas-phase ultraviolet absorption spectrum of nitric acid vapor

Ultrasensitive ultraviolet-visible 20 fs absorption spectroscopy of low vapor pressure molecules in the gas phase.

We describe an ultrasensitive pump-probe spectrometer for transient absorption measurements in the gas phase and in solution. The tunable UV pump and the visible (450-740 nm) probe pulses are generated by two independently tunable noncollinear optical parametric amplifiers, providing a temporal resolution of 20 fs. A homebuilt low gain photodetector is used to accommodate strong probe pulses wi...

The infrared absorption spectrum of the gas phase neutral benzoic acid monomer and dimer

The Ultraviolet Absorption Spectrum of Pepsin

The ultraviolet absorption spectrum of Northrop's pure crystalline pepsin has been determined. The curve of calculated molecular extinction coefficients is given. There is noted a general resemblance of the absorption curve for pepsin to that for urease and tyrosine; the absorption band is maximum at 2750-2800 A.micro., minimum near 2500. A slight hump on either side of the peak of the extincti...

Ultraviolet absorption spectrum of chlorine peroxide, ClOOCl.

The photolysis of chlorine peroxide (ClOOCl) is understood to be a key step in the destruction of polar stratospheric ozone. This study generated and purified ClOOCl in a novel fashion, which resulted in spectra with low impurity levels and high peak absorbances. The ClOOCl was generated by laser photolysis of Cl2 in the presence of ozone, or by photolysis of ozone in the presence of CF2Cl2. Th...

Effects of Temperature, Pressure and Water Vapor on Gas Phase Infrared Absorption by CO2

Full description of an absorption band is complex, but approximate expressions can be used over limited ranges of absorber mole fraction, pressure and pathlength. It can be shown that the “non-overlapping line approximation” applies at ambient pressure and CO2 mole fraction over the short pathlengths found in LI-COR infrared gas analyzers (Wolfe and Zissis, 1978). This leads to a “scaling law” ...