Ab Initio and Density Functional Studies of Substituent Effects of an A−U Base Pair on the Stability of Hydrogen Bonding

1999 ◽  
Vol 103 (42) ◽  
pp. 8516-8523 ◽  
Author(s):  
Shun-ichi Kawahara ◽  
Takeshi Wada ◽  
Susumu Kawauchi ◽  
Tadafumi Uchimaru ◽  
Mitsuo Sekine
Keyword(s):  
Hydrogen Bonding ◽  
Ab Initio ◽  
Base Pair ◽  
Density Functional ◽  
Substituent Effects ◽  
Functional Studies ◽  
The Stability

Ab initio density functional studies on the stability of tetrathiocyanato complexes of Zn(II), Cd(II) and Hg(II)

1997 ◽  
Vol 255 (1) ◽  
pp. 211-214 ◽  
Author(s):  
Nobuhiro Fukushima ◽  
Gouichi Iisaka ◽  
Masahiko Saito ◽  
Kenji Waizumi
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Functional Studies ◽  
The Stability

scholarly journals One-Dimensional Organic–Inorganic Material (C6H9N2)2BiCl5: From Synthesis to Structural, Spectroscopic, and Electronic Characterizations

2021 ◽  
Vol 22 (4) ◽  
pp. 2030
Author(s):  
Hela Ferjani ◽  
Hammouda Chebbi ◽  
Mohammed Fettouhi
Keyword(s):  
Hydrogen Bonding ◽  
Density Functional ◽  
Crystal Packing ◽  
Diffuse Reflectance Spectrum ◽  
Enrichment Ratio ◽  
One Dimensional ◽  
Organic Part ◽  
Fukui Indices ◽  
The Stability ◽  
The One

The new organic–inorganic compound (C6H9N2)2BiCl5 (I) has been grown by the solvent evaporation method. The one-dimensional (1D) structure of the allylimidazolium chlorobismuthate (I) has been determined by single crystal X-ray diffraction. It crystallizes in the centrosymmetric space group C2/c and consists of 1-allylimidazolium cations and (1D) chains of the anion BiCl52−, built up of corner-sharing [BiCl63−] octahedra which are interconnected by means of hydrogen bonding contacts N/C–H⋯Cl. The intermolecular interactions were quantified using Hirshfeld surface analysis and the enrichment ratio established that the most important role in the stability of the crystal structure was provided by hydrogen bonding and H···H interactions. The highest value of E was calculated for the contact N⋯C (6.87) followed by C⋯C (2.85) and Bi⋯Cl (2.43). These contacts were favored and made the main contribution to the crystal packing. The vibrational modes were identified and assigned by infrared and Raman spectroscopy. The optical band gap (Eg = 3.26 eV) was calculated from the diffuse reflectance spectrum and showed that we can consider the material as a semiconductor. The density functional theory (DFT) has been used to determine the calculated gap, which was about 3.73 eV, and to explain the electronic structure of the title compound, its optical properties, and the stability of the organic part by the calculation of HOMO and LUMO energy and the Fukui indices.

scholarly journals Density functional studies of the dipole polarizabilities of the linear polyacenes benzene through nonacene

2005 ◽  
Vol 3 (2) ◽  
pp. 361-369 ◽  
Author(s):  
Alan Hinchliffe ◽  
Beatrice Nikolaidi ◽  
Humberto Soscún Machado
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Correlation Coefficients ◽  
Statistical Correlation ◽  
Tensor Component ◽  
Dipole Polarizability ◽  
Functional Studies ◽  
Absolute Agreement ◽  
Different Levels ◽  
Dipole Polarizabilities

AbstractWe report Ab Initio studies of the electric dipole polarizability of the linear polyacene series benzene through nonacene. A number of Ab Initio studies were done at different levels of theory for benzene, with all remaining Ab Initio calculations being at the B3LYP/6-311G(2d, 1p)//B3LYP/6-311+G(2d, 1p) level of theory. We find that the NN tensor component shows a constant increment of 20 atomic units per ring. AM1 and QSAR-quality empirical calculations show poor absolute agreement with the Ab Initio results but given excellent statistical correlation coefficients with the Ab Initio values. This implies that the results of such cheaper calculations can be suitably scaled for predictive purposes.

scholarly journals Ab initio density-functional studies of 13-atom Cu and Ag clusters

2019 ◽  
Vol 1252 ◽  
pp. 012009
Author(s):  
Dil K. Limbu ◽  
Michael U. Madueke ◽  
Raymond Atta-Fynn ◽  
David A. Drabold ◽  
Parthapratim Biswas
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Functional Studies ◽  
Ag Clusters

scholarly journals Ab initio thermodynamics of liquid and solid water

2019 ◽  
Vol 116 (4) ◽  
pp. 1110-1115 ◽  
Author(s):  
Bingqing Cheng ◽  
Edgar A. Engel ◽  
Jörg Behler ◽  
Christoph Dellago ◽  
Michele Ceriotti
Keyword(s):  
Machine Learning ◽  
Thermodynamic Properties ◽  
Ab Initio ◽  
Density Functional ◽  
Machine Learning Techniques ◽  
Intermediate Step ◽  
Hybrid Functional ◽  
Learning Techniques ◽  
The Stability ◽  
Comprehensive Framework

Thermodynamic properties of liquid water as well as hexagonal (Ih) and cubic (Ic) ice are predicted based on density functional theory at the hybrid-functional level, rigorously taking into account quantum nuclear motion, anharmonic fluctuations, and proton disorder. This is made possible by combining advanced free-energy methods and state-of-the-art machine-learning techniques. The ab initio description leads to structural properties in excellent agreement with experiments and reliable estimates of the melting points of light and heavy water. We observe that nuclear-quantum effects contribute a crucial 0.2 meV/H2O to the stability of ice Ih, making it more stable than ice Ic. Our computational approach is general and transferable, providing a comprehensive framework for quantitative predictions of ab initio thermodynamic properties using machine-learning potentials as an intermediate step.

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