scholarly journals Intramolecular stretching vibrational states and frequency shifts of (H2)2 confined inside the large cage of clathrate hydrate from an eight-dimensional quantum treatment using small basis sets

2019 ◽  
Vol 151 (12) ◽  
pp. 124311 ◽  
Author(s):  
Peter M. Felker ◽  
David Lauvergnat ◽  
Yohann Scribano ◽  
David M. Benoit ◽  
Zlatko Bačić
Keyword(s):  
Clathrate Hydrate ◽  
Basis Sets ◽  
Vibrational States ◽  
Large Cage ◽  
Frequency Shifts ◽  
Quantum Treatment

HCl–H2O dimer: an accurate full-dimensional potential energy surface and fully coupled quantum calculations of intra- and intermolecular vibrational states and frequency shifts

2021 ◽  
Vol 23 (12) ◽  
pp. 7101-7114
Author(s):  
Yang Liu ◽  
Jun Li ◽  
Peter M. Felker ◽  
Zlatko Bačić
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Energy Surface ◽  
Quantum Calculations ◽  
Vibrational States ◽  
Frequency Shifts ◽  
Fully Coupled

The present work reports a new full-dimensional potential energy surface (PES) of the HCl–H2O dimer, and the first fully coupled 9D quantum calculations of the intra- and intermolecular vibrational states of the complex, utilizing this PES.

scholarly journals A study of H2CO•••HF Complex by Advanced Quantum Mechanical Methods

2020 ◽  
Vol 65 (4) ◽  
pp. 304
Author(s):  
A. Amonov ◽  
G. Murodov ◽  
K. G. Tokhadze ◽  
A. Jumabaev ◽  
G. Nurmurodova
Keyword(s):  
Complex Formation ◽  
Vibrational Frequencies ◽  
Binding Energies ◽  
Basis Sets ◽  
Frequency Shifts ◽  
Stable Hydrogen Bond ◽  
Mechanical Methods ◽  
Equilibrium Structures ◽  
Geometric Changes ◽  
Complex Formation Energy

Our research is focused on the ab initio calculations of the equilibrium structures, binding energies, harmonic and anharmonic vibrational frequencies of a hydrogen-bonded complex, which is formed between formaldehyde H2CO and hydrogen fluoride HF, using the Gaussian 09 package of programs with full 6311++G(3df, 3pd) basis sets in the MP2 second-order perturbation theory and CCSD(T) methods. Harmonic and anharmonic vibrational frequencies and intensities of the H2CO···HF complex were calculated by the Gaussian 16 package programs within the same approximation. Geometric changes and frequency shifts at the complex formation were evaluated. The H2CO···HF complex formation energy and the dipole moment were calculated in the CCSD(T)6311++G(3df, 3pd) approximation to be equal, respectively, to 7.78 kcal/mol and 4.2 D. Changes of the geometric, spectral, and energetic parameters of the complex proved the existence of a stable hydrogen bond F–H···O=CH2 between the components.

The DFT Calculations of Structures and EPR Parameters for the Dinuclear Paddle-Wheel Copper(II) Complex {Cu2(μ2-O2CCH3)4}(OCNH2CH3) as Powder or Single Crystal

2017 ◽  
Vol 72 (11) ◽  
pp. 985-994 ◽  
Author(s):  
Chang-Chun Ding ◽  
Shao-Yi Wu ◽  
Yong-Qiang Xu ◽  
Li-Juan Zhang ◽  
Zhi-Hong Zhang ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Single Crystal ◽  
Density Functional ◽  
Hyperfine Coupling ◽  
Basis Sets ◽  
Functional Theory ◽  
Frequency Shifts ◽  
Paddle Wheel ◽  
Epr Parameters ◽  
Mayer Bond Order

AbstractDensity functional theory (DFT) calculations of the structures and the Cu2+g factors (gx, gy and gz ) and hyperfine coupling tensor A (Ax , Ay and Az ) were performed for the paddle-wheel (PW)-type binuclear copper(II) complex {Cu2(μ2-O2CCH3)4}(OCNH2CH3) powder and single crystal. Calculations were carried out with the ORCA software using the functionals BHandHlyp, B3P86 and B3LYP with five different basis sets: 6-311g, 6-311g(d,p), VTZ, def-2 and def2-TZVP. Results were tested by the MPAD analysis to find the most suitable functional and basis sets. The electronic structure and covalency between copper and oxygen were investigated by the electron localisation function and the localised orbital locator as well as the Mayer bond order for the [CuO5] group. The optical spectra were theoretically calculated by the time-dependent DFT module and plotted by the Multiwfn program for the [CuO5] group and reasonably associated with the local structure in the vicinity of the central ion copper. In addition, the interactions between the OCNH2CH3, NH3 and H2O molecules and the uncoordinated PW copper(II) complex were studied, and the corresponding adsorption energies, the frequency shifts with respect to the free molecules and the changes of the Cu–Cu distances were calculated and compared with the relevant systems.

scholarly journals Semiclassical basis sets for the computation of molecular vibrational states

2017 ◽  
Vol 146 (1) ◽  
pp. 014107 ◽  
Author(s):  
F. Revuelta ◽  
E. Vergini ◽  
R. M. Benito ◽  
F. Borondo
Keyword(s):  
Basis Sets ◽  
Vibrational States
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