A high dispersion study of some new absorption bands of CaH and CaD in the ultra-violet region

1968 ◽  
Vol 1 (2) ◽  
pp. 260-265 ◽  
Author(s):  
M Aslam Khan ◽  
M K Afridi
Keyword(s):  
Ultra Violet ◽  
High Dispersion ◽  
Absorption Bands

scholarly journals Ultra-violet emission bands associated with oxygen

1924 ◽  
Vol 105 (734) ◽  
pp. 683-691 ◽  
Keyword(s):  
Wave Length ◽  
Negative Electrode ◽  
Ultra Violet ◽  
Pure Oxygen ◽  
High Dispersion ◽  
Band Spectrum ◽  
Absorption Bands ◽  
Violet Emission ◽  
Negative Band ◽  
Band Spectra

Of emission band spectra generally attributed to oxygen the best known is the negative band spectrum with four strong heads at λλ6420-6300; λλ6010- 5960; λλ5630-5550; λλ5290-5200. In addition there are several other fainter bands about λλ5900-5840; λλ6790-6700; λ6200; λ4980, etc. This spectrum appears with considerable intensity in the yellowish-white glow surrounding the negative electrode of a discharge tube containing pure oxygen, while at lower pressures it is visible along the capillary of the tube. The diffuse character of the bands under the dispersion of an ordinary prism spectrograph renders such wave-length determinations of little value however, except as serving for identification of the bands, and they do not appear to have been measured under high dispersion. The spectrum has been investigated by numerous observers, and although it has not been found in absorption there is general agreement that it arises from an oxygen molecule. In the far ultra-violet (λλ1830-1920) Schumann, using a fluorite spectrograph, was the first to obtain emission and absorption bands of oxygen. These bands were investigated in some detail by Steubing ( loc. cit. ), who confirmed Schumann's observations and showed that the system consists of some five bands extending from λλ1831—1845; λλ1848—1863; λλ1864—1881; λλ1882—1899; λλ1900-1919. Each head consists of about eleven lines giving the appearance of being degraded to the red; and the most refrangible head is the strongest of the five. He was also able to excite in this region the fluorescence spectrum of oxygen. It was found to coincide in position with the emission bands, though the intensity distribution in the spectrum was somewhat different. The two less refrangible heads, it should be mentioned, were observed in fluorescence only. The bands were attributed by him to an O 2 molecule and this appears to have been accepted by later workers; though Kayser took exception to these views.

scholarly journals A coma-free super-high resolution optical spectrometer using 44 high dispersion sub-gratings

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hua-Tian Tu ◽  
An-Qing Jiang ◽  
Jian-Ke Chen ◽  
Wei-Jie Lu ◽  
Kai-Yan Zang ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectral Resolution ◽  
Wavelength Region ◽  
Ultra Violet ◽  
High Spectral Resolution ◽  
Visible Range ◽  
High Dispersion ◽  
Charge Coupled Device ◽  
Wide Range ◽  
High Resolution Spectrometer

AbstractUnlike the single grating Czerny–Turner configuration spectrometers, a super-high spectral resolution optical spectrometer with zero coma aberration is first experimentally demonstrated by using a compound integrated diffraction grating module consisting of 44 high dispersion sub-gratings and a two-dimensional backside-illuminated charge-coupled device array photodetector. The demonstrated super-high resolution spectrometer gives 0.005 nm (5 pm) spectral resolution in ultra-violet range and 0.01 nm spectral resolution in the visible range, as well as a uniform efficiency of diffraction in a broad 200 nm to 1000 nm wavelength region. Our new zero-off-axis spectrometer configuration has the unique merit that enables it to be used for a wide range of spectral sensing and measurement applications.

scholarly journals Ultra-violet transparency of the lower atmosphere, and relative poverty in Ozone

1918 ◽  
Vol 94 (660) ◽  
pp. 260-268 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Solar Spectrum ◽  
Ultra Violet ◽  
Lower Atmosphere ◽  
Atmospheric Ozone ◽  
Absorption Bands ◽  
Relative Poverty ◽  
Narrow Bands

Many years ago it was suggested by Hartley* that the limit of the solar spectrum towards the ultra-violet was attributable to absorption by atmospheric ozone, which, as he showed, would give rise to a general absorption beginning at about the place where the solar spectrum ends. In a recent paper by Prof. A. Fowler and myself,† the evidence for this view was very much strengthened. For it was shown that just on the limits of extinction the solar spectrum shows a series of narrow absorption bands which are eventually merged in the general absorption, and these narrow bands are precisely reproduced in the absorption spectrum of ozone. For my own part, I do not feel any doubt that ozone in the atmosphere is the effective cause limiting the solar spectrum.

Spectra of sodium and potassium azide crystals coloured by ultra-violet and X -ray radiation

1959 ◽  
Vol 251 (1264) ◽  
pp. 27-40 ◽  
Keyword(s):  
Sodium Salt ◽  
Ultra Violet ◽  
Liquid Nitrogen Temperature ◽  
Mechanism Of Formation ◽  
Potassium Salts ◽  
Absorption Bands ◽  
X Ray ◽  
Rate Of Increase ◽  
Potassium Azide ◽  
Sodium And Potassium

The spectra of sodium and potassium azide crystals that had been coloured by irradiation with both ultra-violet and X-ray radiation for varying periods at liquid-nitrogen temperature have been recorded. From these results and from measurements of the rate of increase of intensity of the various absorption bands with time, together with the changes observed on raising the temperature, the nature and mechanism of formation of some of the centres are deduced. The different behaviour of the sodium and potassium salts under irradiation and the different effects produced by the two types of irradiation, particularly with the sodium salt, are discussed.

scholarly journals An investigation of the absorption spectra of water and ice, with reference to the spectra of the major planets

1928 ◽  
Vol 120 (785) ◽  
pp. 296-302 ◽  
Keyword(s):  
Water Vapour ◽  
Absorption Spectra ◽  
Atomic Hydrogen ◽  
Solar Spectrum ◽  
High Dispersion ◽  
The Sun ◽  
Absorption Bands ◽  
Weak Band ◽  
General Similarity ◽  
Dense Band

The spectra of the light of the sun reflected from the major planets—Jupiter, Saturn, Uranus and Neptune—were photographed by Slipher in 1909. These spectra showed a general similarity in that there were a number of absorption bands superimposed on the ordinary solar spectrum. The intensity and width of these absorptions varied from planet to planet, increasing in general from Jupiter to Neptune in the order quoted. Of the chemical identity of the bands little is known. Some—C and F, fig. 4, for example—can be attributed to absorption by atomic hydrogen in the atmospheres of the planets; others might be due to water-vapour, though other water-vapour bands do not appear. The outstanding unidentified bands which are common to the spectra of the four planets are (see fig. 4, Plate 10):— ( a ) At λ = 5430 Å.—A rather weak band in the spectra of Jupiter and Saturn, but very strong in those of Uranus and Neptune. ( b ) At λ = 6190 Å.—This is the mid-point of a conspicuous and dense band appearing in the spectra of all the four planets, broadening from a width of some 50 Å in that of Jupiter to some 200 Å in that of Neptune. Although quite strong in the spectrum of Jupiter, it showed no tendency to become resolved in the high dispersion plates taken of the spectrum of this planet. ( c ) A strong double band at λ = 7200 to 7260 Å recorded in the spectra of Saturn and Jupiter, and probably just as strong in those of Uranus and Neptune, but not recorded because of the insensitiveness of the plates in this region.

Origin and distribution of the polyatomic molecules in the atmosphere

1956 ◽  
Vol 236 (1205) ◽  
pp. 187-193 ◽  
Keyword(s):  
Water Vapour ◽  
Ultra Violet ◽  
Ground Level ◽  
Absorption Bands ◽  
Ultra Violet Radiation ◽  
Low Concentrations ◽  
Vertical Distributions ◽  
Similar Accuracy ◽  
Lapse Rates ◽  
Made In

Of those gases which occur in the upper atmosphere and have strong absorption bands in the infra-red part of the spectrum and which must, therefore, be con­sidered when calculating the absorption and radiation of heat in the atmosphere, only carbon dioxide is uniformly mixed with the air at all heights which we are likely to be dealing with; it will not be considered further here. The vertical distributions of water vapour and ozone are of great interest, particularly when considered together. Water vapour, originating at ground level, usually decreases rather rapidly with increasing height, particularly in the lower stratosphere. This leads to extremely low concentrations at a height of about 15 km. On the other hand, ozone, being formed by the action of solar ultra-violet radiation at a height of 30 km or more, decreases in concentration downwards. We find, therefore, ozone diffusing downwards and water vapour diffusing upwards through the same region of the atmosphere, but, as we shall see, with very different lapse rates. Water vapour The standard hygrometers which are used to measure the humidity from free balloons are only satisfactory at temperatures above about 235°K, and our knowledge of the humidity at high levels in the atmosphere is almost entirely dependent on measurements made with frost-point hygrometers carried on air­craft. The work of the Meteorological Research Flight of the British Meteorological Office is notable for the very large number of measurements made from Mosquito aircraft to a height of about 12 km and more recently from Canberra aircraft to 15 km. Most unfortunately, hardly any measurements having similar accuracy have been made in other parts of the world. However, at the present time Dr A. W. Brewer is in north Norway making such measurements with the kind co-operation of the Norwegian Air Force and I had hoped that some results might have been available in time to report them at this Discussion (see note at end of paper).

scholarly journals The absorption spectra of conjugated dienes in the vacuum ultra-violet (1)

1940 ◽  
Vol 174 (957) ◽  
pp. 220-234 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Electronic Structures ◽  
Spectroscopic Data ◽  
Ultra Violet ◽  
Conjugated Dienes ◽  
Strong Absorption ◽  
Absorption Bands ◽  
Lennard Jones ◽  
Vacuum Ultra Violet

Butadiene is important as the simplest example of resonance between two conjugated double bonds. The comparison of its ultra-violet absorption spectrum with that of ethylene might be expected to give some indication of the way the π electrons of the molecule are affected by the resonance. The electronic structures of a number of molecules for which resonance is important have been worked out theoretically by Hückel (1935), Lennard- Jones (1937), Sklar (1937) and Mulliken (1939 a and b ). The purpose of the present work is to obtain spectroscopic data with which the theoretical expectations can be compared. As most of the strong absorption bands of these molecules occur at wave-lengths less than 2000 A, the investigation falls naturally into the region of vacuum spectroscopy.

scholarly journals The coagulation of protein by sunlight

1922 ◽  
Vol 93 (651) ◽  
pp. 235-248 ◽  
Keyword(s):  
Temperature Coefficient ◽  
Tap Water ◽  
Wave Length ◽  
Ultra Violet ◽  
Protein Molecule ◽  
Mercury Vapour ◽  
Absorption Bands ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Mercury Vapour Lamp

It was first shown by Dreyer and Hanssen (1) in 1917 that ultra-violet light produced a change in protein solutions which appeared to be similar to coagulation by heat. They exposed various solutions in quartz chambers to the light of a Bang lamp with iron and silver electrodes. Vitellin was found most easily coagulated, while globulin, albumin and fibrinogen showed a decreasing sensitivity to ultra-violet rays in the order mentioned. These investigators also discovered that acids markedly increase the rate of precipitation. Soret (2) had shown in 1883 that there are absorption bands in the extreme ultra-violet region of the spectrum of various proteins, e. g. , casein, ovalbumin, mucin and globulin. Tyrosine likewise has this band in the ultra-violet and Soret attributed to this constituent of the protein molecule its power of absorbing ultra-violet rays. In this connection Harris and Hoyt (3) carried out some interesting experiments on the protective power of various substances for paramœcium cultures exposed to ultra-violet radiations. They found that gelatin peptone, amino-benzoic acid, cystine, leucine and especially tyrosine possessed the power of detoxicating ultra-violet rays when placed as a thin layer of aqueous solution over paramœcium cultures under a quartz-mercury lamp. The toxicity of the radiations for paramœcia or protoplasm in general can be understood in the light of the discovery of Dreyer and Hanssen coupled with that of Soret. From a physico- chemical standpoint Bovie (4) has published a study of the coagulation of proteins by ultra-violet light. By exposing solutions of crystalline ovalbumin, both dialysed and containing electrolytes, to the light of a mercury-vapour lamp, he came to the conclusion that there were two reactions involved in the coagulation of ovalbumin by ultra-violet light. The first is a photochemical one with a low temperature coefficient,—denaturation; and the second is one with a higher temperature coefficient of two and is dependent upon the electrolytes present,—coagulation. While using solutions dialysed against tap water Bovie made the observation that the protein appeared to become sensitive to light of longer wave-length, for his control tubes in glass were slowly coagulated.

scholarly journals The absorption spectrum of formic acid in the vacuum ultra-violet

1937 ◽  
Vol 162 (908) ◽  
pp. 110-120 ◽  
Keyword(s):  
Electronic Structure ◽  
Formic Acid ◽  
Absorption Spectra ◽  
Ultra Violet ◽  
The Body ◽  
Hydrogen Atoms ◽  
Absorption Bands ◽  
Additional Absorption ◽  
Lyman Continuum ◽  
Vacuum Ultra Violet

Absorption spectra in the far ultra-violet region of the spectrum have recently assumed an important role in fixing the electronic structures of polyatomic molecules. This has been especially true of organic molecules such as acetylene, ethylene, the alkyl halides, alcohols, ethers and ketones. While all “molecular electrons” (i. e. those not contained in inner shells) can be expected to give rise to absorption bands in the region 2000–1000 A, it most frequently happens that one special electron type dominates the absorption. For example, the excitation of non-bonding pπ electrons dominate the absorption of methyl and ethyl iodides (Price 1936 a ); so-called “lone pairs” located on the oxygen atoms are responsible for all the strong bands of water, formaldehyde, etc. (Mulliken 1935 a, b ; Price 1935 a , 1936 b ). In order to obtain discrete absorption bands, which are desirable for the purposes of interpreting electronic structure, it is usually necessary to take the very simplest organic molecule containing the group we wish to study. Thus for molecules of the type R 1 COO R 2 ( R being an alkyl group or a hydrogen atom) it has been found that only the simplest of these, namely formic acid, shows discrete absorption bands. The interpretation of the electronic structure of the carboxyl group will therefore depend to a considerable extent upon the analysis of these discrete bands. From the discussion which follows it will be easy to see why the continuous absorption from the larger molecules of the type R 1 COO R 2 follows roughly the envelope of the discrete absorption of HCOOH except in so far as it is enhanced in certain regions by additional absorption from C—C and C—H bonding electrons or suffers small shifts to longer wave-lengths as a result of the substitution of hydrogen atoms by alkyl groups. The experimental technique employed in obtaining absorption spectra in the vacuum ultra-violet has been described elsewhere (Collins and Price 1934). The Lyman continuum serves as the background against which the 19340. The Lyman continuum serves as the background against which the absorption is observed, and the gas under investigation is allowed to flow continuously through the body of the spectrograph.

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