Optically Active Vibrations of Doped Lanthanum Copper Oxide Compound (La2−xMxCuO4)

1993 ◽  
Vol 47 (3) ◽  
pp. 296-299 ◽  
Author(s):  
Ken Ohwada ◽  
Ginji Fujisawa
Keyword(s):  
Copper Oxide ◽  
Force Field ◽  
Optically Active ◽  
Lattice Vibrations ◽  
Layer Model ◽  
Normal Coordinate ◽  
Lanthanum Copper Oxide ◽  
Oxide Compound ◽  
Infinite Layer ◽  
Valence Force Field

Normal coordinate analysis of the optically active vibrations of doped lanthanum copper oxide (La2– x M xCuO4) has been made, with the assumption of an infinite [(CuO2)O2]6– layer model. On the basis of the results of this treatment, some of the observed bands so far reported have been successfully assigned to the Cu-O lattice vibrations. The force constants concerning Cu-O bonds have been obtained within the framework of a modified valence force field. It has been found that the present analysis based on the infinite layer model is useful for assigning the relatively high vibrational frequencies observed at the center (wave vector k = 0) of the first Brillouin zone in La2– x M xCuO4.

Optically Active Vibrations of Lithium and α-Sodium Uranium Hexafluorides (LiUF6 and α-NaUF6)

1989 ◽  
Vol 43 (4) ◽  
pp. 714-718 ◽  
Author(s):  
Ken Ohwada
Keyword(s):  
Low Temperature ◽  
Force Field ◽  
Electronic Absorption ◽  
Structural Model ◽  
Electronic Absorption Spectra ◽  
Optically Active ◽  
Lattice Vibrations ◽  
Normal Coordinate ◽  
Valence Force Field ◽  
Intramolecular Vibrations

Normal coordinate analyses of the optically active vibrations of LiUF6 and α-NaUF6 have been made, with the assumption of an idealized structural model. On the basis of the results of this treatment, all of the observed bands so far reported have been successfully assigned to the intramolecular vibrations (UF6−) as well as the optically active lattice vibrations [M+(Li, Na) … UF6−]. The force constants concerning U-F and M-F bonds have been obtained within the framework of the modified valence force field. It has been found that the present analysis, based on a whole crystal, is powerful not only for assigning the optically active lattice vibrations but also for elucidating the vibronic structure of the electronic absorption spectra obtained at low-temperature measurements.

Molecular Vibrations of Gallium Trichloride Monomer with Application of the Keating Bending

1985 ◽  
Vol 40 (7) ◽  
pp. 714-718 ◽  
Author(s):  
B. N. Cyvin ◽  
S. J. Cyvin ◽  
G. Diaz ◽  
T. Mogstad ◽  
E. Rytter
Keyword(s):  
Force Field ◽  
Field Approximation ◽  
Normal Coordinate ◽  
Frequency Shifts ◽  
Mean Amplitudes Of Vibration ◽  
Central Force Field ◽  
Valence Force Field ◽  
New Type ◽  
The Mean ◽  
Gallium Trichloride

The vibrational spectra and previous normal coordinate analyses of GaCl3 are reviewed. The valence force field (VFF), Keating force field (KFF) and central force field (CFF) are investigated, taking into account isotopic frequency shifts and the mass influence on Coriolis constants. It seems that KFF is an appropriate force field approximation. In its definition a new type of internal coordinates, the Keating's bending, is invoked. A final force Field is tentatively determined and used to calculate the mean amplitudes of vibration.

Vibrational Spectra and Normal Coordinate Calculations of Chlorophosphazene Compounds. III. Polydichlorophosphazene

1982 ◽  
Vol 36 (3) ◽  
pp. 277-281 ◽  
Author(s):  
M. M. Coleman ◽  
J. Zarian ◽  
P. C. Painter
Keyword(s):  
Force Field ◽  
Vibrational Spectra ◽  
Reasonable Agreement ◽  
Normal Modes ◽  
Normal Coordinate ◽  
Valence Force ◽  
Valence Force Field

Vibrational spectra and normal coordinate calculations of polydichlorophosphazene (PDP) are presented. The valence force field derived previously from the two conformers of octachlorocyclotetraphosphazene was directly transferred to a distorted “cis-plan” helical model of PDP without refinement. A reasonable agreement between the observed and calculated frequencies was obtained and the assignment of the normal modes of PDP is discussed.

scholarly journals The Vibrational Spectra of Silane and Germane Derivatives. Part IV. The Infrared and Raman Spectra of the Iodo(methyl)germanes

1971 ◽  
Vol 49 (18) ◽  
pp. 2931-2936 ◽  
Author(s):  
J. W. Anderson ◽  
G. K. Barker ◽  
J. E. Drake And ◽  
R. T. Hemmings
Keyword(s):  
Force Field ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
A Priori ◽  
Normal Coordinate Analysis ◽  
Infrared And Raman Spectra ◽  
Normal Coordinate ◽  
Valence Force ◽  
Valence Force Field ◽  
Fundamental Frequencies

The infrared and Raman spectra of the series of iodo(methyl)germanes, CH3GeI3, (CH3)2GeI2, and (CH3)3GeI have been recorded. A normal coordinate analysis based on a modified valence force field confirms the a priori assignments for all of the fundamental frequencies except the torsional modes.

Vibrational analysis and force field for some secondary iodides

1977 ◽  
Vol 55 (2) ◽  
pp. 310-317 ◽  
Author(s):  
G. Crowder ◽  
Zahra Najafi
Keyword(s):  
Force Field ◽  
Infrared Spectra ◽  
Vibrational Analysis ◽  
Zero Order ◽  
Average Error ◽  
Average Difference ◽  
Normal Coordinate ◽  
Valence Force ◽  
Valence Force Field ◽  
Wave Numbers

Normal coordinate calculations were made for 2-iodopropane and the three conformers of 2-iodobutane. A forty-seven parameter modified valence force field was used that fit eighty-four frequencies of those four molecules in the 250–1500 cm−1 region with an average error of 4.8 cm−1, or 0.6%. Infrared spectra were obtained for 2-iodopentane and 3-iodopentane, and zero-order normal coordinate calculations were made for three conformers of 2-iodopentane and for five conformers of 3-iodopentane. The SHH, SHH′, and SCH conformers of 2-iodopentane are present, along with one or two unidentified ones, and 3-iodopentane exists as a mixture of the SHH, SHH′, SCH, and SCH′ conformers. The force constants that were determined for the four conformers of 2-iodopropane and 2-iodobutane were transferred to the two secondary iodo-pentanes with good success. The average difference between observed and calculated wave-numbers for 164 frequencies of seven conformations of these two compounds was 5.8 cm−1.

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