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Investigations of infra-red spectra ..., Edizione 65
William Weber Coblentz
Visualizzazione completa - 1906
Abney absorption bands absorption spectra acetylene alcohol aniline Aschkinass band found band occurs benzaldehyde benzene benzene band benzene derivatives benzene nucleus bolometer carbon cell cent CH3-groups complex deep bands deflection detected dispersion effect electrical electrodes emission band emission lines emission spectra ethyl eucalyptol examined fatty acids film flame fluorite gases group of atoms H atom harmonic heat heater hence hydrogen increase infra-red intensity investigated large absorption bands large spectrometer limonene liquid longer wave-lengths maxima maximum metals minimum deviation molecular weight molecule mustard oils nitrogen noticed observed obtained OH-group opacity opaque oxygen Paschen petroleum distillates Phys Physik pinene present pressure Prism at Variable pyridine radiation radiometer region ring rock salt shifted shows small spectrometer sodium lines solid solution spectrometer slit temperature terpenes thickness thiophene tion transmission curve transmission minima transparent tube vacuum-tube vanes vibration visible spectrum water of crystallization xylenes
Pagina 113 - nucleus," in common with many of the compounds studied, which causes absorption bands, characteristic of the great groups of organic compounds, but we do not know what that " something " is. The presence of these groups of
Pagina 322 - On the .other hand, the other bands increase in intensity with increase in pressure, become a maximum at about 2 mm. pressure, then decrease in intensity with a further increase in pressure, which agrees with observations in the visible spectrum. All lines increase in intensity with increase in current as found in the visible spectrum.
Pagina 319 - ... which is proportional to the mean square of the ionic speeds will attain a maximum. At a still lower pressure, on account of the scarcity of the molecules, there will be fewer collisions in a given time, the ionization will decrease and the " electrical temperature
Pagina 109 - Of course, as is well known now, the nearest approximation to such a law is Balmer's Law and the numerous other convergent series formulae used by Kayser and Runge, and by others. Nevertheless, in spite of these warnings, and fully realizing the danger from lack of dispersion, experimental errors, etc., I venture to call attention to certain marked absorption bands which occur so frequently, in positions which so closely fulfill this relation, that it is necessary...
Pagina 320 - ... the neutral gas molecules. The gas molecule as a whole will suffer an increase in its kinetic energy, and, in colliding with other molecules, will cause a rise in the thermal temperature of the gas. With increase in pressure, ie, in the number of gas molecules, the number of collisions will increase, the intensity of the thermal radiation will increase but will not pass through a maximum, as is true of the other bands, because a stage will be arrived at where there will be a decrease in the ionization...
Pagina 320 - At a high pressure the constricted portion of the vacuum tube is the hotter while at low pressure it is quite cool, and the region surrounding the electrodes is the hotter. Third, the emission increases with the pressure (equivalent to an increase in the thickness of the emitting layer) and approaches a limiting value. Paschen (loc. cit.) has found for CO2 at atmospheric pressure, in a brass tube heated by a bunsen burner that a column 7 cm. long emitted and absorbed energy just as strong as a column...
Pagina 105 - Fig. 10. Illustrating the persistence of the benzene bands at 3.25/7 and 6.75^ in the spectra of its derivatives. Considering the bands of ammonia and of the compounds containing NH2, or certain ones containing nitrogen, the coincidence appears to be somewhat accidental. Farther in the infra-red we have numerous cases of the coincidence of absorption bands. As a whole the most definite conclusion we can draw, at present, is that the alcohols have a characteristic band at about 2.95 // just as the...
Pagina 111 - ... using a radiometer, two mirror spectrometers and rock salt prism. Out of a total number of at least 135 compounds examined with the rock salt prism, 131 have been recorded in this paper. They include solids, liquids, and gases. In addition to this, 19 compounds were examined to 2.7 p, using a quartz prism.
Pagina 97 - ... tion of heat waves, it will simplify matters to discuss each of these topics separately. A few transmission curves are included to give the reader an idea of their general appearance. Effect of Structure. — In order to learn what effect a group of atoms in a molecule has upon infra-red absorption spectra, the most logical procedure is to study isomeric compounds in order to determine fully that the phenomenon is intramolecular, and after that attempt to locate the particular group of atoms...
Pagina 98 - H atoms in benzene do we find bands, eg, 3.43 fjt, in common with those of the chain compounds. If, then, we had no knowledge of organic chemistry, the evidence presented here would be sufficient to conclude that we are dealing with two distinct classes of compounds.