Beyond the Visible Region

As the twentieth century proceeded, and modem technology for the detection and analysis of the light output from pyrotechnics and other light-emitting articles continued to improve, interest on the military side moved from the visible into the infrared region of electromagnetic radiation. 

A pyrotechnic flare that emits a high-intensity output of visible and infrared radiation, to dazzle the detector 

Use of a pyrotechnic smoke, where the smoke particles absorb and scatter the radiation that is emitted by the warm target object, causing it to not be distinguishable from the background 

The use of multiple decoys that are emitting infrared radiation of a type and energy output that mimics what the detector is specifically looking for, and thereby divert attention away from the target 

Theory of colored flame production, RDTN 71, Crane, IN U.S. Naval Ammunition Depot, 1964. 

---

Compound 20 is noteworthy in that it was the first azo dye reported whose absorption band is shifted beyond the visible region into the... 

You will, of course, be familiar with the visible part of the electromagnetic spectrum. This radiation is, by definition, visible to the human eye. Other detection systems reveal types of radiation which are beyond the visible region of the spectrum, with these being classified as radiowaves, microwaves, infrared, ultraviolet. X-rays, and... 

Compound 2.6 is noteworthy in that it was the first azo dye reported whose absorption band is shifted beyond the visible region into the near-infrared region of the spectrum, showing a /Lma of 778 nm in dichloromethane. The extreme bathochromicity of this dye may be explained by a combination of the effects discussed throughout this... 

The polyene produced has a high extinction coefficient, and as it increases in size the range of radiation absorbed extends into and beyond the visible region, resulting in the sample moving from... 

The significance of collision-induced absorption for the planetary sciences is well established (Chapter 7) reviews and updates appeared in recent years [115, 165, 166, 169-173]. Numerous efforts are known to model experimental and theoretical spectra of the various hydrogen bands for the astrophysical applications [170, 174-181]. More recently, important applications of colhsional absorption in astrophysics were discovered in the cool and extremely dense stellar atmospheres of white dwarf stars [14, 43, 182-184], at temperatures from roughly 3000 to 6000 K. Under such conditions, large populations of vibra-tionally excited H2 molecules exist and collision-induced absorption extends well into the visible region of the spectrum and beyond. Numerous hot bands, high H2 overtone bands, and H2 rotovibrational sum and difference spectral bands due to simultaneous transitions that were never measured in the laboratory must be expected. Ab initio calculations of the collisional absorption processes in the dense atmospheres of such stars have yet to be provided so that the actual stellar emission spectra may be obtained more accurately than presently known. 

Medium effects on wavelength in the visible region are small (beyond three significant figures). 

---