Comparison between molecular geometry and harmonic vibrational frequency predictions from CISD[TQ] and CISDTQ wave functions for hydrogen sulfide

1997 ◽  
Vol 107 (24) ◽  
pp. 10616-10619 ◽  
Author(s):  
Brian C. Hoffman ◽  
C. David Sherrill ◽  
Henry F. Schaefer
Keyword(s):  
Hydrogen Sulfide ◽  
Vibrational Frequency ◽  
Molecular Geometry ◽  
Wave Functions ◽  
Harmonic Vibrational Frequency

scholarly journals Effects of Hydrogen Bonding on the Rotational Dynamics of Water-Like Molecules in Liquids: Insights from Molecular Dynamics Simulations

2020 ◽  
Vol 73 (8) ◽  
pp. 734
Author(s):  
W. A. Monika Madhavi ◽  
Samantha Weerasinghe ◽  
Konstantin I. Momot
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Bonding ◽  
Hydrogen Sulfide ◽  
Spin Relaxation ◽  
Rotational Diffusion ◽  
Molecular Geometry ◽  
Md Simulations ◽  
Water Molecules ◽  
Molecular Reorientation ◽  
Nmr Spin Relaxation

Rotational motion of molecules plays an important role in determining NMR spin relaxation properties of liquids. The textbook theory of NMR spin relaxation predominantly uses the assumption that the reorientational dynamics of molecules is described by a continuous time rotational diffusion random walk with a single rotational diffusion coefficient. Previously we and others have shown that reorientation of water molecules on the timescales of picoseconds is not consistent with the Debye rotational-diffusion model. In particular, multiple timescales of molecular reorientation were observed in liquid water. This was attributed to the hydrogen bonding network in water and the consequent presence of collective rearrangements of the molecular network. In order to better understand the origins of the complex reorientational behaviour of water molecules, we carried out molecular dynamics (MD) simulations of a liquid that has a similar molecular geometry to water but does not form hydrogen bonds: hydrogen sulfide. These simulations were carried out at T=208K and p=1 atm (~5K below the boiling point). Ensemble-averaged Legendre polynomial functions of hydrogen sulfide exhibited a Gaussian decay on the sub-picosecond timescale but, unlike water, did not exhibit oscillatory behaviour. We attribute these differences to hydrogen sulfide’s absence of hydrogen bonding.

Vibrational Frequency Shifts of the Carbonyl Stretching Mode Induced by Solvents: Acetone

1989 ◽  
Vol 43 (6) ◽  
pp. 1053-1055 ◽  
Author(s):  
R. A. Nyquist ◽  
T. M. Kirchner ◽  
H. A. Fouchea
Keyword(s):  
Hydrogen Bonding ◽  
Vibrational Frequency ◽  
Molecular Geometry ◽  
Intermolecular Hydrogen Bonding ◽  
Acceptor Number ◽  
Frequency Shifts ◽  
Solvent Interaction ◽  
Precise Measure ◽  
Solvent Systems ◽  
Solute Solvent Interaction

Variation in the correlations obtained between electron acceptor number (AN) values for each solvent versus the vC=O frequencies for acetone and tetramethylurea in solution with these solvents suggests that the AN values are not a precise measure of solute/solvent interaction for all solute/solvent systems. Factors such as intermolecular hydrogen bonding between solute and solvent and the differences between molecular geometry of the solutes and solvents most likely account for differences in the solute/solvent interaction for different solutes in the same solvents.

An Evaluation of Harmonic Vibrational Frequency Scale Factors

2007 ◽  
Vol 111 (45) ◽  
pp. 11683-11700 ◽  
Author(s):  
Jeffrey P. Merrick ◽  
Damian Moran ◽  
Leo Radom
Keyword(s):  
Vibrational Frequency ◽  
Frequency Scale ◽  
Scale Factors ◽  
Harmonic Vibrational Frequency

Molecular geometry of ribofuranoses obtained from semi-empirical MO calculations

1983 ◽  
Vol 48 (2) ◽  
pp. 504-510
Author(s):  
Jiří Krechl ◽  
Josef Kuthan
Keyword(s):  
Degrees Of Freedom ◽  
Molecular Geometry ◽  
Wave Functions ◽  
Mo Calculations ◽  
Semi Empirical

Molecular geometry of ribofuranoses I - VIII has been optimized with respect to all degrees of freedom on the basis of CNDO/2 wave functions. The results obtained are confronted with previous results of partial optimizations.

scholarly journals Prediction of Mechanism and Thermochemical Properties of O3+ H2S Atmospheric Reaction

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Morteza Vahedpour ◽  
Reza Baghary ◽  
Freshte Khalili
Keyword(s):  
Hydrogen Sulfide ◽  
Reaction Mechanism ◽  
Oxygen Atom ◽  
Atmospheric Pressure ◽  
Vibrational Frequency ◽  
Main Reaction ◽  
Intrinsic Reaction Coordinate ◽  
Thermochemical Properties ◽  
Frequency Calculation ◽  
Atmospheric Reaction

Ozone and hydrogen sulfide reaction mechanism including a complex was studied at the B3LYP/6-311++G(3df,3pd) and CCSD/6-311++G(3df,3pd)//B3LYP/6-311++G(3df,3pd) levels of computation. The interaction between sulfur atom of hydrogen sulfide and terminal oxygen atom of ozone produces a stable H2S-O3complex with no barrier. With the decomposition of this complex, four possible product channels have been found. Intrinsic reaction coordinate, topological analyses of atom in molecule, and vibrational frequency calculation have been used to confirm the suggested mechanism. Thermodynamic data atT= 298.15 K and the atmospheric pressure have been calculated. The results show that the production of H2O + SO2is the main reaction channel with ΔG° = −645.84 kJ/mol. Rate constants of H2S + O3reaction show two product channels, SO2 + H2O and HSO + HOO, which compete with each other based on the temperature.

Harmonic vibrational frequency scaling factors for the new NDDO Hamiltonians: RM1 and PM6

2007 ◽  
Vol 105 (19-22) ◽  
pp. 2597-2605 ◽  
Author(s):  
Z. A. Fekete ◽  
E. A. Hoffmann ◽  
T. Körtvélyesi ◽  
B. Penke
Keyword(s):  
Vibrational Frequency ◽  
Frequency Scaling ◽  
Scaling Factors ◽  
Harmonic Vibrational Frequency
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