Krypton fluoride

A typical example might involve use of a krypton fluoride excimer laser operating at 249 nm with a pulse duration around 100 nanoseconds and a pulse repetition rate which can be varied up to 200 Hz. For metal deposition, energy densities in the range from 0.1 to 1 J/cm per pulse are typical. 

Finally, it is interesting to note that under exposure to krypton fluoride (KrF) excimer laser radiation supphed in several shots of 350 mJ/cm the S-layer is not ablated but car-... 

Laser Flash Photolysis at 248 nm of TDI-PU. MDI-PUE. and Model Compounds. Figures 1 and 2 show the transient absorption spectra of MDI-PUE (5.5 X lO-3 g/dL) and TDI-PU (2.3 X 10 3 g/dL) in THF at a 2.0 ns delay after pulsing with a krypton fluoride excimer laser (Xex=248 nm) in air and nitrogen saturated samples. Both spectra have common peaks in nitrogen saturated solutions (shown by arrows) at 310 nm, 330-360 nm (broad), and above 400 nm (broad, diffuse absorbance).. The MDI-PUE sample has an additional and quite distinctive peak at 370 nm. In the presence of air, the peak at 370 nm for MDI-PUE is completely extinguished, while the sharp peaks at 310 nm for TDI-PU and MDI-PUE and the broad band above 400 nm are only marginally quenched by oxygen. 

British chemist Sir William Ramsay Noble gas that gives off a bluish light when subjected to electrical charge often used for airport runway lighting forms only one known compound, krypton fluoride. 

The krypton fluorides, KrF2 and KrF4, are moderately stable, but the combination of the relatively high molecular weight of krypton and low fluorine content (< 50 wt. %) results in performance capabilities of little real interest. The fluorides of the light noble gases have not been isolated although some spectroscopic evidence for their existence has... 

Among the noble gas fluorides, the binary fluorides of xenon have received the most attention as fluorinating agents. Krypton fluorides seem to be more exotic novelties than real reagents. 

Reaction of HC=NH+ salts of [AsFft] or RpCsN adducts of AsF5 with KrFj in nonaqueous solvents lead to salts characterized as [HCsN—Kr —F]+[AsFfi] and [RFC=N — Kr—F]+[AsFfi] (RF = CF, C2Fj. n-C F7). Krypton fluoride has proven extremely useful as a fluorinating agent It is 50 kJ mol-1 more exothermic than fluorine. F, It may be used to raise metals to unusual oxidation states 21... 

Krypton-fluoride laser -use m fusion energy pUSION ENERGY] (Vol 12)... 

Irradiation with a krypton fluoride excimer laser can be employed for the preparation of highly unstable 1,2-dilluoroacetylene from 1.2-difluorodiiodoethene.167... 

One of the methods under development at AT T Bell Laboratories for submicron lithography is deep ultraviolet projection photolithography. (O Fine line definition is obtained by use of 248 nm light and a lens of large numerical aperture. Because of the large chromatic aberration of the quartz lens a spectrally line-narrowed krypton fluoride excimer laser is used as a light source. 

Beside XeOs and Xe04, some xenon oxyfluorides are also thermally unstable compounds. They may detonate, particularly at higher temperatures. Other derivatives of the xenon and krypton fluorides involving ligands less electronegative than fluorine should also be assmned to be of low thermodynamic stability. Many derivatives such as perchlorates and trifluoroacetates are known to be explosive. 

The syntheses of fluorides of krypton and radon have also been demonstrated. Krypton fluorides are harder to make and probably are less stable than the corresponding xenon fluorides. Fluorides of radon would be expected to be more... 

Turner, J.J. and G.C. Pimentel (1963). Krypton fluoride Preparation by the matrix isolation technique. Science 140, 974—975. 

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