Intensities in the infra-red spectrum of benzene

1956 ◽  
Vol 238 (1213) ◽  
pp. 245-255 ◽  
Keyword(s):  
Dipole Moment ◽  
Experimental Error ◽  
Carbon Skeleton ◽  
Absolute Intensities ◽  
Bond Stretching ◽  
Infra Red ◽  
Out Of Plane ◽  
Plane Bending ◽  
The Absolute

The absolute intensities of the infra-red active fundamental vibrations of benzene, mono-deuterobenzene, and para -dideuterobenzene have been measured and interpreted in terms of the dipole moment derivatives: ∂ μ z /∂ S 11 = -1·43 D/Å; ∂ μ y /∂ S 18 a = - 0·51 D/Å; ∂ μ y /∂ S 19 a = -0·32 D/Å; ∂ μ y /∂ S 20 a = -0·78 D/Å. All three spectra are consistent with these values. The ‘effective’ C—H bond moment for in-plane bending is 0·31 D and for out-of-plane bending 0·61 D. The value for the C—H bond-stretching dipole-moment derivative is 0·45 D/Å with the H atom becoming less positive as the bond stretches. In-plane distortions of the carbon skeleton which leave the C—H bond directions unchanged, produce zero dipole moment within the experimental error.

The effect of intermolecular forces upon the vibrations of molecules in the crystalline state I. The out-of-plane bending of the carbonate ion in aragonite minerals

1963 ◽  
Vol 275 (1362) ◽  
pp. 295-309 ◽  
Keyword(s):  
Intermolecular Forces ◽  
Absolute Intensities ◽  
Carbonate Ion ◽  
Nearest Neighbours ◽  
Bending Mode ◽  
Infra Red ◽  
Out Of Plane ◽  
Plane Bending ◽  
Oxygen Bond ◽  
Dipole Energy

The infra-red absorption of polycrystalline BaCO 3 , SrCO 3 , and CaCO 3 , the latter in both the aragonite and calcite modifications, has been measured in the region 600 to 2000 cm -1 . Absolute intensities were determined for each of the three fundamental bands of the carbonate ion, by the method of extrapolation to infinite dilution of the carbonate in the alkali halide matrix. The band due to the out-of-plane bending mode was examined under high resolution, the samples employed having been enriched to a 50/50 ratio of 12 C/ 13 C. Intermolecular coupling in this band, which is revealed by the isotopic solid solution, has been interpreted as arising primarily from interaction of the dipoles produced during the vibration. The dipole derivatives calculated from this coupling agree fairly well with those estimated from the absolute intensities. Various sources of error are discussed, and in particular, an estimate is made of the dipole-dipole energy summed over the entire lattice, instead of merely for nearest neighbours. The carbon-oxygen bond moment during the vibration has an effective value of from 1.3 to 1.7 debyes.

The absolute intensities of the infra-red fundamentals of methane

1960 ◽  
Vol 16 (7) ◽  
pp. 840-852 ◽  
Author(s):  
K.L. Armstrong ◽  
H.L. Welsh
Keyword(s):  
Absolute Intensities ◽  
Infra Red ◽  
The Absolute

Intensities of infra-red bands - V. Bond polar properties in dimethyl acetylene

1955 ◽  
Vol 228 (1174) ◽  
pp. 287-297 ◽  
Keyword(s):  
Negative Charge ◽  
Positive Charge ◽  
Hydrogen Atoms ◽  
Fundamental Vibration ◽  
Absolute Intensities ◽  
Similar Work ◽  
Infra Red ◽  
The Absolute

The absolute intensities of all except one of the infra-red fundamental vibration bands of dimethyl acetylene have been determined, and the results have been used to compute polar properties of the C—H and C—C bonds. It has been found that if the very probable assump­tion is made that the acetylenic carbon atoms carry a residual negative charge, the hydrogen atoms in the C—H bonds must carry a residual positive charge. The probable value of the C—H dipole is about 0-4 Debye, and that of the C—C≡ bond about 1 Debye. Comparisons have been made with the results of similar work with related molecules.

Self-consistent-field calculations of the vibrational spectrum of undoped and doped transpolyacetylene

1985 ◽  
Vol 63 (7) ◽  
pp. 1553-1561 ◽  
Author(s):  
Andrea Peluso ◽  
Max Seel ◽  
Janos Ladik
Keyword(s):  
Vibrational Spectrum ◽  
Raman Band ◽  
Broad Band ◽  
Consistent Field ◽  
Defect Sites ◽  
Self Consistent ◽  
Bond Stretching ◽  
Out Of Plane ◽  
Self Consistent Field ◽  
Plane Bending

Semiempirical self-consistent-field calculations are carried out to compute the force constants for various cluster models of periodic transpolyacetylene and of neutral and charged soliton and polaron defects. The phonon spectrum of undoped polyacetylene is analyzed and compared with the vibrational spectrum of various polyene chains in which soliton or polaron defects have been introduced in a random way. The results support the interpretation that the 1100 cm−1 Raman band of undoped polyacetylene should be ascribed to a C—C single bond stretching motion weakly coupled to a C—H in-plane bending vibration. The 1292 cm−1 infrared peak of pure transpolyacetylene is ascribed to the C—H in-plane deformation, the strong adsorption at 1015 cm−1 has to be assigned to an infrared-active out-of-plane C—H deformation. The new narrow band around 1300 cm−1 seen in the infrared spectrum of doped polyacetylene is ascribed to C—C bond stretching, the additional very broad band between 800 and 900 cm−1 results from in-plane C—C—H bending and C—H out-of-plane bending motions involving relaxed bond lengths of the defect sites. The interpretation is not uniquely in favor of the soliton picture, polaron defects can serve as alternative explanation.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane, and Mixed Mode Bending Under Seismic Load: An Experimental Approach

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Dynamic Behavior ◽  
Failure Modes ◽  
Seismic Load ◽  
Piping System ◽  
Shake Table ◽  
Shake Table Tests ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Plane Bending

Pressurized piping systems used for an extended period may develop degradations such as wall thinning or cracks due to aging. It is important to estimate the effects of degradation on the dynamic behavior and to ascertain the failure modes and remaining strength of the piping systems with degradation through experiments and analyses to ensure the seismic safety of degraded piping systems under destructive seismic events. In order to investigate the influence of degradation on the dynamic behavior and failure modes of piping systems with local wall thinning, shake table tests using 3D piping system models were conducted. About 50% full circumferential wall thinning at elbows was considered in the test. Three types of models were used in the shake table tests. The difference of the models was the applied bending direction to the thinned-wall elbow. The bending direction considered in the tests was either of the in-plane bending, out-of-plane bending, or mixed bending of the in-plane and out-of-plane. These models were excited under the same input acceleration until failure occurred. Through these tests, the vibration characteristic and failure modes of the piping models with wall thinning under seismic load were obtained. The test results showed that the out-of-plane bending is not significant for a sound elbow, but should be considered for a thinned-wall elbow, because the life of the piping models with wall thinning subjected to out-of-plane bending may reduce significantly.

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