Infrared spectra, rotational correlation functions, band moments, and intermolecular mean squared torques of methane dissolved in liquid noble gases

1969 ◽  
Vol 47 (16) ◽  
pp. 2915-2920 ◽  
Author(s):  
A. Cabana ◽  
R. Bardoux ◽  
A. Chamberland
Keyword(s):  
Absorption Spectra ◽  
Infrared Spectra ◽  
Correlation Functions ◽  
Noble Gases ◽  
Liquid Argon ◽  
Liquid Methane ◽  
The Mean ◽  
Rotational Correlation

Extensive measurements of the infrared (i.r.) absorption spectra of liquid methane and of methane dissolved in liquid argon, krypton, and xenon have been carried out. Band profiles for the v3 and v4 modes of CH4 and CD4 are reported. From these profiles the rotational correlation functions have been calculated. Comparison of the experimental functions with the functions calculated for the free rotators at the appropriate temperatures reveals that each molecule rotates freely for only 1.3 × 10−13 s before it undergoes a hard collision; the same result was obtained for all the systems investigated. Difficulties in obtaining accurate values of the band moments are discussed and suggestions for overcoming them are presented. Values ranging from 6.9 to 8.2 × 104 cm−2 have been obtained for the mean squared torques acting on methane in the various solutions.

Infrared spectra, rotational correlation functions, and intermolecular mean squared torques in compressed gaseous methane

1968 ◽  
Vol 46 (11) ◽  
pp. 1331-1340 ◽  
Author(s):  
R. L. Armstrong ◽  
S. M. Blumenfeld ◽  
C. G. Gray
Keyword(s):  
Correlation Functions ◽  
Theoretical Calculations ◽  
Dominant Contribution ◽  
Dispersion Interactions ◽  
Fundamental Vibration ◽  
Order Of Magnitude ◽  
The Mean ◽  
Vibration Rotation ◽  
Experimental Values ◽  
Rotational Correlation

Extensive measurements of the methane ν3 and ν4 fundamental vibration–rotation bands in CH4–He mixtures and the ν3 band in CH4–He, CH4–N2, and CD4–He mixtures have been carried out in infrared absorption at 295 °K to pressures of 3000 atm. Some profiles of the ν3 band in CH4–Ar mixtures and in pure CH4 have also been obtained. Rotational correlation functions, band moments, and intermolecular mean squared torques have been determined from the ν3 band profiles. Theoretical calculations of the mean squared torque due to anisotropic multipolar, induction and dispersion interactions have been carried out. The theoretical and experimental torques are in order-of-magnitude agreement for the CH4–N2 and CH4–CH4 systems; for CH4–He, CD4–He, and CH4–Ar the theoretical values are two to three orders of magnitude too small to account for the experimental values, indicating that in these cases the dominant contribution to the torques is given by the anisotropic overlap forces.

Some studies in inorganic complexes. XXV. Cobalt(II) and nickel(II) complexes of 2-Acetamidopyridine and 2-Aminomethyl-6-rnethylpyridine, and the cobalt(II) complex of 2-Methylpyridine-6-carboxylic acid

1969 ◽  
Vol 22 (9) ◽  
pp. 1841 ◽  
Author(s):  
KH Shaw ◽  
GJ Sutton
Keyword(s):  
Magnetic Properties ◽  
Carboxylic Acid ◽  
Absorption Spectra ◽  
Infrared Spectra ◽  
Reflectance Spectra ◽  
Inorganic Complexes

Complexes of cobalt(II) and nickel(II) with the ligands 2- acetamidopyridine (acpy) and 2-aminomethyl-6-methylpyridine (mepic) have been prepared and studied. They included [Co(acpy)2X2], [Co(mepic)2X2], [Ni(acpy)2X2], and [Ni-(mepic)2X2], in which X is Cl, Br, I, or NCS; [Co(acpy)2(NO3)2], [Co(mepic)2(NO3)2], [Ni(acpy)2(NO3)2], [Ni(mepic)3NO3]NO3, [Co(acpy)3](ClO4)2, [Co(mepic)3](ClO4)2, [Co(mepic)3](CoCl4), [Ni(acpy)2(H2O)2](ClO4)2, and [Ni(mepic)2(H2O)2](ClO4)2. The inner complex of 2-methylpyridine-6- carboxylic acid [Co(mepiac)2,2H2O)] was also isolated. In all cases, the magnetic properties, conductances, reflectance spectra, absorption spectra, and infrared spectra are in agreement with the concept that they are spin-free, six-coordinate octahedral complexes. The substance [Ni(mepic)2NO3]NO3 contains both bidentate and ionic nitrate.

scholarly journals The absorption spectra of halogens and inter-halogen compounds in solution in carbon tetrachloride

1929 ◽  
Vol 124 (795) ◽  
pp. 604-616 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Carbon Tetrachloride ◽  
Absorption Spectra ◽  
Spectroscopic Data ◽  
Chemical Interaction ◽  
Chemical Compounds ◽  
Absorption Bands ◽  
Halogen Compounds ◽  
Inert Solvent ◽  
The Mean

When two solutions are mixed the absorption spectrum of the new solution will be the mean of those of the separate solutions provided that no chemical interaction occures. The mere fact of a departure from additivity does not, however, necessarily denote the formation of true chemical compounds. The solute or solutes may undergo solvation, loosely bound aggregates may occur, and even when marked deviations from the simple law of mixtures are observed it is rarely possible to prove the quantitative formation of a given chemical compound from spectroscopic data alone. The above considerations apply with some force to the problem of the absorption spectra of halogens and inter-halogen compounds in an inert solvent. The three elements show perfectly characteristic absorption bands, they are known to interact with the formation of some quite stable compounds, some relatively stable compounds, and some apparently very unstable compounds.

scholarly journals The infra-red absorption spectra of quartz and fused Silica from 1 to 7·5 μ II-Experimental results

1936 ◽  
Vol 153 (879) ◽  
pp. 328-339 ◽  
Keyword(s):  
Water Vapour ◽  
Absorption Spectra ◽  
Wave Length ◽  
Fused Silica ◽  
Experimental Results ◽  
Wave Number ◽  
Infra Red ◽  
The Mean ◽  
Point To Point ◽  
Maximum Discrepancy

The accuracy of calibration, as already mentioned, was checked against CO 2 and water vapour bands. With the quartz prism the instrument could be set to show the 2·7 μ CO 2 bands resolved and within about 0·003μ of their known wave-lengths*; i. e., within 4 cm -1 . With the fluorite prism, resolution at 2·7 μ was inferior, but the structure of the water vapour band centred at 6·3 μ provided about 20 points for the checking of wave-lengths. Here the maximum discrepancy was 5 cm -1 and the mean discrepancy about 1·5 cm -1 , The wave-number error, therefore, is not libels to exceed 5 cm -1 in any part of the range investigated. The fraction of radiation transmitted by a specimen was measured to three figures and a mean of two or three observations at least taken for each wave-length setting. The accuracy varies from specimen to specimen and from point to point throughout the spectrum, depending on the magnitude of the galvanometer deflexions obtainable. The error is, however, nowhere likely to be greater than 0·01 and for much of the work is of the order of 0·002.

A discussion on infared astronomy - Expected infrared spectra of gaseous nebulae

1969 ◽  
Vol 264 (1150) ◽  
pp. 241-247 ◽  
Keyword(s):  
Infrared Spectra ◽  
Galactic Plane ◽  
Interstellar Extinction ◽  
Mount Everest ◽  
Gaseous Nebulae ◽  
The Galaxy ◽  
The Mean ◽  
Spiral Arm

If we are asked why we want to use the infrared to observe gaseous nebulae, we might reply with George Mallory, who was asked why he wanted to climb Mount Everest, ‘Because its there’. More specifically, one reason is the very great space penetration possible in the infrared. Diffuse nebulae characteristically are close to the galactic plane, and interstellar extinction therefore prevents the observation of distant objects. At MATHS FORMULA the mean range to which diffuse nebulae can easily be observed is about 1500 parsecs (pc), while many of these nebulae are so reddened as to be nearly unobservable at Hβ. It is for this reason that at present the observation of diffuse nebulae is almost entirely limited to our own spiral arm and its immediate neighbours. However, because of the decrease of interstellar extinction to longer wavelengths, at 1 μm the range of observation would be about 3000 pc; at 2 μm about 10 000 pc, comparable with the distance to the centre of the Galaxy; and at 10μm, about 100 000 pc, far larger than the diameter of the Galaxy. (The form of the interstellar reddening curve is from Whitford 1958.)

The Dynamic Behaviour of a Crystal During Defect Jumps

1986 ◽  
Vol 41 (8) ◽  
pp. 1051-1059 ◽  
Author(s):  
R. Vogelsang ◽  
C. Hoheisel
Keyword(s):  
Correlation Functions ◽  
Dynamic Behaviour ◽  
High Density ◽  
Mean Square ◽  
Pure Crystal ◽  
Pure Fluid ◽  
Fcc Lattice ◽  
Quantitative Results ◽  
The Mean

In continuation of a previous paper, M D simulations of vacancy jump in an fcc-lattice have been performed, due to an increased averaging process, quantitative results for a number of correlation functions are obtained, which throw light on the details of the highly cooperative mechanism of vacancy jumps involving some fifty neighbouring particles. This Part II is mainly concerned with self correlation functions while part III focusses on distinct correlation functions. Both the mean square displacements and the velocity correlations of the particles have been considered and were analysed in comparison with those of a pure crystal and a pure fluid of high density.

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