ChemInform Abstract: FORCE FIELD, DIPOLE MOMENT DERIVATIVES, AND VIBRONIC CONSTANTS OF BENZENE FROM A COMBINATION OF EXPERIMENTAL AND AB INITIO QUANTUM CHEMICAL INFORMATION

1981 ◽  
Vol 12 (29) ◽  
Author(s):  
P. PULAY ◽  
G. FOGARASI ◽  
J. E. BOGGS
Keyword(s):  
Dipole Moment ◽  
Force Field ◽  
Ab Initio ◽  
Quantum Chemical ◽  
Chemical Information

Trimethylammoniodiformylmethylide: Structure and charge distribution

1980 ◽  
Vol 45 (1) ◽  
pp. 80-91 ◽  
Author(s):  
Vladimír Král ◽  
Zdeněk Arnold
Keyword(s):  
Dipole Moment ◽  
Total Energy ◽  
Ab Initio ◽  
Charge Distribution ◽  
Quantum Chemical ◽  
Energy Minimum ◽  
Chemical Methods ◽  
Quantum Chemical Methods ◽  
Total Energy Minimum

Geometric arrangement of trimethylammoniodiformylmethylide (I) and charge distribution in this compound were calculated by quantum chemical methods (EHT, CNDO/2, INDO, PCILO, MINDO/2, ab initio). Total energy minimum was found for the arrangement If. The experimentally found dipole moment agrees very well with that calculated for this conformation.

Overtones of the Si−H Stretching−Bending Polyad in SiHD3: Internal Coordinate Force Field, ab initio Dipole Moment Surfaces, and Band Intensities

2001 ◽  
Vol 105 (25) ◽  
pp. 6065-6072 ◽  
Author(s):  
Hai Lin ◽  
Hans Bürger ◽  
Sheng-Gui He ◽  
Lan-Feng Yuan ◽  
Jürgen Breidung ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Force Field ◽  
Ab Initio

The Si–H stretching–bending overtone polyads of SiHF3: Assignments, band intensities, internal coordinate force field, and ab initio dipole moment surfaces

2001 ◽  
Vol 115 (3) ◽  
pp. 1378-1391 ◽  
Author(s):  
Hai Lin ◽  
Hans Bürger ◽  
El Bachir MKadmi ◽  
Sheng-Gui He ◽  
Lan-Feng Yuan ◽  
...  
Keyword(s):  
Dipole Moment ◽  
Force Field ◽  
Ab Initio

scholarly journals Molecular simulation of the thermophysical properties and phase behaviour of impure CO2 relevant to CCS

2016 ◽  
Vol 192 ◽  
pp. 415-436 ◽  
Author(s):  
Alexander J. Cresswell ◽  
Richard J. Wheatley ◽  
Richard D. Wilkinson ◽  
Richard S. Graham
Keyword(s):  
Physical Properties ◽  
Force Field ◽  
Ab Initio ◽  
Molecular Simulation ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Force Fields ◽  
Phase Behaviour ◽  
Suitable Model ◽  
Wide Range

Impurities from the CCS chain can greatly influence the physical properties of CO2. This has important design, safety and cost implications for the compression, transport and storage of CO2. There is an urgent need to understand and predict the properties of impure CO2 to assist with CCS implementation. However, CCS presents demanding modelling requirements. A suitable model must both accurately and robustly predict CO2 phase behaviour over a wide range of temperatures and pressures, and maintain that predictive power for CO2 mixtures with numerous, mutually interacting chemical species. A promising technique to address this task is molecular simulation. It offers a molecular approach, with foundations in firmly established physical principles, along with the potential to predict the wide range of physical properties required for CCS. The quality of predictions from molecular simulation depends on accurate force-fields to describe the interactions between CO2 and other molecules. Unfortunately, there is currently no universally applicable method to obtain force-fields suitable for molecular simulation. In this paper we present two methods of obtaining force-fields: the first being semi-empirical and the second using ab initio quantum-chemical calculations. In the first approach we optimise the impurity force-field against measurements of the phase and pressure–volume behaviour of CO2 binary mixtures with N2, O2, Ar and H2. A gradient-free optimiser allows us to use the simulation itself as the underlying model. This leads to accurate and robust predictions under conditions relevant to CCS. In the second approach we use quantum-chemical calculations to produce ab initio evaluations of the interactions between CO2 and relevant impurities, taking N2 as an exemplar. We use a modest number of these calculations to train a machine-learning algorithm, known as a Gaussian process, to describe these data. The resulting model is then able to accurately predict a much broader set of ab initio force-field calculations at comparatively low numerical cost. Although our method is not yet ready to be implemented in a molecular simulation, we outline the necessary steps here. Such simulations have the potential to deliver first-principles simulation of the thermodynamic properties of impure CO2, without fitting to experimental data.

Millimetre-wave and infrared spectroscopy of Br13 CN: anharmonic force field of cyanogen bromide from spectroscopic data and ab initio calculations

1997 ◽  
Vol 90 (3) ◽  
pp. 495-497
Author(s):  
CLAUDIO ESPOSTI ◽  
FILIPPO TAMASSIA ◽  
CRISTINA PUZZARINI ◽  
RICCARDO TARRONI ◽  
ZDENEK ZELINGER
Keyword(s):  
Infrared Spectroscopy ◽  
Force Field ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Spectroscopic Data ◽  
Cyanogen Bromide ◽  
Millimetre Wave ◽  
Anharmonic Force

Evaluation of Chemotherapeutic Activity of the Selected Bases’ Analogues of Nucleic Acids Supported by ab initio Various Quantum Chemical Calculations

2020 ◽  
Vol 16 (2) ◽  
pp. 93-103 ◽  
Author(s):  
Piotr Kawczak ◽  
Leszek Bober ◽  
Tomasz Bączek
Keyword(s):  
Biological Activity ◽  
Nucleic Acids ◽  
Ab Initio ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Structural Parameters ◽  
Principal Component ◽  
Polarizable Continuum Model ◽  
Activity Data ◽  
Qsar Models

Background: Pharmacological and physicochemical classification of bases’ selected analogues of nucleic acids is proposed in the study. Objective: Structural parameters received by the PCM (Polarizable Continuum Model) with several types of calculation methods for the structures in vacuo and in the aquatic environment together with the huge set of extra molecular descriptors obtained by the professional software and literature values of biological activity were used to search the relationships. Methods: Principal Component Analysis (PCA) together with Factor Analysis (FA) and Multiple Linear Regressions (MLR) as the types of the chemometric approach based on semi-empirical ab initio molecular modeling studies were performed. Results: The equations with statistically significant descriptors were proposed to demonstrate both the common and differentiating characteristics of the bases' analogues of nucleic acids based on the quantum chemical calculations and biological activity data. Conclusion: The obtained QSAR models can be used for predicting and explaining the activity of studied molecules.

Sign in / Sign up

Export Citation Format

Share Document