Bond stretching force constants and compressibilities of nitride, oxide, and sulfide coordination polyhedra in molecules and crystals

1994 ◽  
Vol 5 (6) ◽  
pp. 349-355 ◽  
Author(s):  
F. C. Hill ◽  
G. V. Gibbs ◽  
Monte B. Boisen
Keyword(s):  
Force Constants ◽  
Coordination Polyhedra ◽  
Bond Stretching ◽  
Nitride Oxide

scholarly journals The Raman spectra of Bis(hexamethylenetetramine)-iodine(I) and -bromine(I) perchlorates

1977 ◽  
Vol 30 (5) ◽  
pp. 1123 ◽  
Author(s):  
GA Bowmaker ◽  
RJ Knappstein
Keyword(s):  
Raman Spectra ◽  
Halogen Bond ◽  
Interaction Force ◽  
Force Constants ◽  
Bond Stretching

The low-wavenumber (<200 cm-1) Raman spectra of bis(hexamethylenetetramine)iodine(I) perchlorate and bis(hexamethylenetetramine)bromine(I) perchlorate have been measured, and the nitrogen-halogen symmetric stretching mode of the cation has been assigned for each compound. The nitrogen-halogen bond stretching and interaction force constants for the cations have been calculated, and these are found to be very similar to those for the corresponding bis(pyridine)halogen(I) cations.

Schwingungsspektren und Kraftkonstanten der Hexahalogeno-Komplexe des Technetium(IV) und Rhenium(IV)

1969 ◽  
Vol 24 (3) ◽  
pp. 403-407 ◽  
Author(s):  
Klaus Schwochau ◽  
Wolfgang Krasser
Keyword(s):  
Force Field ◽  
Infrared Spectra ◽  
Force Constants ◽  
Octahedral Structure ◽  
Fundamental Vibration ◽  
Rhenium Complexes ◽  
Valence Force ◽  
Valence Force Field ◽  
Bond Stretching

The Raman and infrared spectra of the potassium and caesium salts of [TcX6]-- and [ReX6]-- (X = F, Cl, Br, I) have been measured in the range from 1000 to 45 cm-1. The force constants are determined in the valence force field and in the standard Urey-Bradley field on the basis of the Oh-symmetry. The fundamental vibration ν6 is calculated from the force constants. Apart from the fluoro-compounds the bond-stretching force constants of the technetium complexes are shown to be smaller than those of the analogous rhenium complexes. Except for the iodo-compounds a distortion of the octahedral structure progressive in degree towards X = F can be concluded from the splitting of degeneracies.

Binary Mixed Dinitrogen–Carbonyl Complexes of Nickel(0), Ni(N2)m(CO)4−m (where m = 1–3)

1973 ◽  
Vol 51 (16) ◽  
pp. 2737-2746 ◽  
Author(s):  
E. P. Kündig ◽  
M. Moskovits ◽  
G. A. Ozin
Keyword(s):  
Dipole Moments ◽  
Force Constants ◽  
Carbonyl Complexes ◽  
Transition Dipole ◽  
Warm Up ◽  
Vibrational Assignments ◽  
Diffusion Controlled ◽  
Transition Dipole Moments ◽  
Bond Stretching ◽  
Bonding Properties

Nickel atoms have been cocondensed in various 12C16O/14N2, 12C16O/14N2/Ar, and 12C18O/14N2/15/N2/Ar matrices and the infrared and Raman spectra of the products recorded at 4.2–10 °K. In addition to the infrared absorptions associated with the known compounds Ni(N2)4 and Ni(CO)4, other NN and CO stretching modes are observed which can be ascribed to the mixed carbonyl–dinitrogen species Ni(N2)m (CO)4−m where m = 1–3. Confirmation of the molecular constitutions and vibrational assignments of the isolated species was obtained from (a) variable concentration experiments in which either N2 or CO was arranged to be in excess, (b) diffusion controlled warm-up experiments in the range 10–35 °K, and (c) isotope substitution experiments using 14N2/15N2/12C18O/Ar matrices in which the total nitrogen to carbon monoxide ratio was varied. Cotton–Kraihanzel kCO and kNN force constants are computed for the mixed compounds Ni(CO)3(N2), Ni(CO)2(N2)2, and Ni(CO)(N2)3 and trends within the series are discussed in terms of the σ-donor and π-acceptor bonding properties of the N2 and CO ligands. An analysis is presented in which the changes in the CO and N2 bond stretching force constants in passing from Ni(CO)m to Ni(CO)m(N2)4−m and from Ni(N2)4−m to Ni(CO)m(N2)4−m are related to the change in σ and π orbital populations. The results of that analysis indicate that CO is both a better σ donor and a better π acceptor than N2. Integrated absorbances of the bands associated with the species Ni(CO)m(N2)4−m are measured and are used to compute ratios of the transition dipole moments (μco′)m and [Formula: see text] for CO and N2 respectively. The observed trends for (μco′)m and [Formula: see text] as functions of m are found to be in keeping with the changes in the respective CO and N2 π orbital populations.

Microscopic Mechanisms for Reduced Static Dielectric Constants in Si-O-F Alloy Films

1997 ◽  
Vol 476 ◽  
Author(s):  
H. Yang ◽  
G. Lucovsky
Keyword(s):  
Dielectric Constant ◽  
Alloy System ◽  
Dielectric Constants ◽  
Force Constants ◽  
Significant Fraction ◽  
Alloy Films ◽  
Bond Stretching ◽  
Effective Charges ◽  
Static Dielectric Constants ◽  
Recent Attention

AbstractThere is considerable interest in insulators with static dielectric constants lower than SiO2; an alloy system attracting recent attention is Si-O-F. Alloying of F atoms into plasma-deposited SiO2 films leads to major changes in the SiO2 bond-stretching and -bending infrared bands accounting for a significant fraction of the reduction in the dielectric constant. These changes are explained by F induced modifications of force constants and effective charges of the neighboring Si-O-Si groups.

The kinetics of conformational transitions: Effect of variation of bond angle bending and bond stretching force constants

1981 ◽  
Vol 75 (9) ◽  
pp. 4441-4445 ◽  
Author(s):  
Eugene Helfand ◽  
Z. R. Wasserman ◽  
Thomas A. Weber ◽  
Jeffrey Skolnick ◽  
John H. Runnels
Keyword(s):  
Bond Angle ◽  
Conformational Transitions ◽  
Force Constants ◽  
Bond Stretching ◽  
Kinetics Of
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