scholarly journals Abnormally high oscillator strengths of the graphene nanoribbons electronic spectrum: quantum chemistry calculations

RSC Advances ◽  
2016 ◽  
Vol 6 (79) ◽  
pp. 75937-75942 ◽  
Author(s):  
V. G. Maslov ◽  
Andrey I. Svitenkov ◽  
V. V. Krzhizhanovskaya
Keyword(s):  
Quantum Chemistry ◽  
Electronic Spectrum ◽  
Graphene Nanoribbons ◽  
Oscillator Strengths ◽  
Chemistry Method ◽  
Hartree Fock ◽  
Quantum Chemistry Calculations ◽  
Semi Empirical ◽  
Quantum Chemistry Method

Armchair-edged narrow graphene nanoribbons (GNRs) are modelled by semi-empirical Hartree–Fock based quantum chemistry method ZINDO/S-CI. ​Abnormally high oscillator strengths of over 200 are found in long GNRs (length > 150 hexagonal carbon rings).

PREDICTIONS ON THE FORMATION AND BOND PERFORMANCE OF SOME ETTRINGITES BY A QUANTUM CHEMISTRY METHOD

1997 ◽  
Vol 27 (7) ◽  
pp. 1085-1092 ◽  
Author(s):  
Chen Xin ◽  
Yu Jinghua ◽  
Liu Futian ◽  
Yue Yunlong ◽  
Chang Jun
Keyword(s):  
Quantum Chemistry ◽  
Chemistry Method ◽  
Bond Performance ◽  
Quantum Chemistry Method

An Elucidation of the Interaction Between Pt Particles and CeO2 Surfaces Using Tight-Binding Quantum Chemistry Method

2010 ◽  
Vol 53 (7-10) ◽  
pp. 700-706 ◽  
Author(s):  
S. Jung ◽  
A. Suzuki ◽  
H. Tsuboi ◽  
N. Hatakeyama ◽  
A. Endou ◽  
...  
Keyword(s):  
Quantum Chemistry ◽  
Tight Binding ◽  
Chemistry Method ◽  
Quantum Chemistry Method

scholarly journals Infrared Spectrum for the New Exobiological Nanomolecules Asi, Csi, Tsi and Gsi

2021 ◽  
pp. 25-31
Author(s):  
Ricardo Gobato ◽  
Alireza Heidari ◽  
Lauro Figueroa Valverde ◽  
Abhijit Mitra
Keyword(s):  
Infrared Spectrum ◽  
Quantum Chemistry ◽  
Ab Initio ◽  
Basis Sets ◽  
Minimal Basis ◽  
Hartree Fock ◽  
Standard Bases ◽  
Quantum Chemistry Calculations ◽  
Computational Calculations ◽  
Correlation Consistent

The core of the work is based on the replacement of carbon atoms by silicon atoms, on the basis of four standard bases of DNA: A, C, G and T (adenine, cytosine, guanine, thymine). Determining with minimum computational methods via ab initio Hartree-Fock methods, infrared spectrum and their peak absorbance frequencies. The option for simple replacement of carbon by silicon is due to the peculiar characteristics between both. Atomic interactions under non-carbon conditions were studied, with only the Hydrogen, Silicon, Nitrogen and Oxygen atoms, in CNTP, for the four standard bases of DNA, A, C, G and T, thus obtaining by quantum chemistry four new compounds, named here as: ASi, CSi, GSi and TSi. Computational calculations admit the possibility of the formation of such molecules, their existence being possible via quantum chemistry. Calculations obtained in the ab initio Unrestricted and Restrict Hartree-Fock method, (UHF and RHF) in the set of basis used Effective core potential (ECP) minimal basis, UHF CEP-31G (ECP split valance) and UHF CEP-121G (ECP triple-split basis), CC-pVTZ (Correlation-consistent valence-only basis sets triple-zeta) and 6-311G**(3df, 3pd) (Gaussian functions quadruple-zeta basis sets).

The effect of nitrido, azide, and nitrosyl ligands on magnetization densities and magnetic properties of iridium PNP pincer-type complexes

RSC Advances ◽  
2015 ◽  
Vol 5 (102) ◽  
pp. 84311-84320
Author(s):  
Daniel Stuart ◽  
Paweł Tecmer ◽  
Paul W. Ayers ◽  
Katharina Boguslawski
Keyword(s):  
Magnetic Properties ◽  
Quantum Chemistry ◽  
Chemistry Method ◽  
Quantum Chemistry Method

The magnetisation density of different iridium PNP pincer-type complexes depends on the chosen quantum chemistry method.

Double-helix PnLin chains: novel potential nonlinear optical materials

2018 ◽  
Vol 20 (18) ◽  
pp. 12618-12623 ◽  
Author(s):  
Yangyang Hu ◽  
Xiaodong Xu ◽  
Yingjie Jiang ◽  
Guiling Zhang ◽  
Weiqi Li ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Quantum Chemistry ◽  
Optical Materials ◽  
Nonlinear Optical ◽  
Double Helix ◽  
Nonlinear Optical Materials ◽  
Cd Spectra ◽  
Chemistry Method ◽  
Circular Dichroïsm ◽  
Quantum Chemistry Method

The structures, circular dichroism (CD) spectra and nonlinear optical (NLO) responses of a series of inorganic double-helix chains, PnLin (n = 6–12), have been investigated using the quantum chemistry method.

scholarly journals A mixed quantum chemistry/machine learning approach for the fast and accurate prediction of biochemical redox potentials and its large-scale application to 315,000 redox reactions

2018 ◽  
Author(s):  
Adrian Jinich ◽  
Benjamin Sanchez-Lengeling ◽  
Haniu Ren ◽  
Rebecca Harman ◽  
Alán Aspuru-Guzik
Keyword(s):  
Machine Learning ◽  
Quantum Chemistry ◽  
Redox Reactions ◽  
Large Scale ◽  
Computational Cost ◽  
Accurate Method ◽  
Redox Potentials ◽  
Quantum Chemistry Calculations ◽  
Quantitative Understanding ◽  
Semi Empirical

AbstractA quantitative understanding of the thermodynamics of biochemical reactions is essential for accurately modeling metabolism. The group contribution method (GCM) is one of the most widely used approaches to estimating standard Gibbs energies and redox potentials of reactions for which no experimental measurements exist. Previous work has shown that quantum chemical predictions of biochemical thermodynamics are a promising approach to overcome the limitations of GCM. However, the quantum chemistry approach is significantly more expensive. Here we use a combination of quantum chemistry and machine learning to obtain a fast and accurate method for predicting the thermodynamics of biochemical redox reactions. We focus on predicting the redox potentials of carbonyl functional group reductions to alcohols and amines, two of the most ubiquitous carbon redox transformations in biology. Our method relies on semi-empirical quantum chemistry calculations calibrated with Gaussian Process (GP) regression against available experimental data. Our approach results in higher predictive power than the GCM at a low computational cost. We design and implement a network expansion algorithm that iteratively reduces and oxidizes a set of natural seed metabolites, and demonstrate the high-throughput applicability of our method by predicting the standard potentials of more than 315,000 redox reactions involving approximately 70,000 compounds. Additionally, we developed a novel fingerprint-based framework for detecting molecular environment motifs that are enriched or depleted across different regions of the redox potential landscape. We provide open access to all source code and data generated.

Radiative lifetimes, branching fractions, and oscillator strengths of high-lying levels in Re I

2019 ◽  
Author(s):  
Yongfan Li ◽  
Sébastien Gamrath ◽  
Patrick Palmeri ◽  
Pascal Quinet ◽  
Qiu Li ◽  
...  
Keyword(s):  
Transition Probabilities ◽  
Branching Fractions ◽  
Laser Induced Fluorescence ◽  
Oscillator Strengths ◽  
Core Polarization ◽  
Radiative Lifetimes ◽  
Time Resolved ◽  
Hartree Fock ◽  
Semi Empirical ◽  
First Time

Abstract Radiative lifetimes of 19 levels in Re I were measured using the time-resolved laser-induced fluorescence method. As far as we know, 15 results are reported for the first time. By combining the experimental lifetimes determined from the present work with theoretical branching fractions obtained by a pseudo-relativistic Hartree–Fock model including core-polarization contributions, a new set of semi-empirical transition probabilities and oscillator strengths for 47 Re I lines from 18 newly measured levels were derived.

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