# intermolecular potentialRecently Published Documents

955
(FIVE YEARS 82)

## H-INDEX

78
(FIVE YEARS 7)

2022 ◽
Vol 43 (2) ◽
Author(s):
Robert Hellmann
Keyword(s):

AbstractThe cross second virial coefficient $$B_{12}$$ B 12 for the interaction between water (H2O) and carbon monoxide (CO) was obtained with low uncertainty at temperatures from 200 K to 2000 K employing a new intermolecular potential energy surface (PES) for the H2O–CO system. This PES was fitted to interaction energies determined for about 58 000 H2O–CO configurations using high-level quantum-chemical ab initio methods up to coupled cluster with single, double, and perturbative triple excitations [CCSD(T)]. The cross second virial coefficient $$B_{12}$$ B 12 was extracted from the PES using a semiclassical approach. An accurate correlation of the calculated $$B_{12}$$ B 12 values was used to determine the dilute gas cross isothermal Joule–Thomson coefficient, $$\phi _{12}=B_{12}-T(\mathrm {d}B_{12}/\mathrm {d}T)$$ ϕ 12 = B 12 - T ( d B 12 / d T ) . The predicted values for both $$B_{12}$$ B 12 and $$\phi _{12}$$ ϕ 12 agree reasonably well with the few existing experimental data and older calculated values and should be the most accurate estimates of these quantities to date.

2021 ◽
Author(s):
Bónis Barcza ◽
Ádám B. Szirmai ◽
Katalin J. Szántó ◽
Attila Tajti ◽
Péter G. Szalay
Keyword(s):

The ground state intermolecular potential of bimolecular complexes of N-heterocycles is analysed for the impact of different terms of the interaction energy as provided by various, conceptually different theories. Novel combinations with several formulations of the electrostatic, Pauli repulsion, dispersion and other contributions are tested for a good performance at both short- and long-distance sides of the potential energy surface for various alignments of the pyrrole dimer as well as the cytosine-uracil complex. The integration of a DFT/CC density embedding scheme and dispersion terms from the effective fragment potential (EFP) method is found to provide very good agreement with the reference CCSD(T) potential overall, but a QM/MM approach using CHELPG atomic point charges for the electrostatic interaction augmented by EFP dispersion and Pauli repulsion contributions comes also close. Both of these schemes has the advantage of not relying on predefined force fields, rather the interaction parameters can be obtained for the system under study, therefore excellent candidates for ab initio modeling.

2021 ◽
Author(s):
Bónis Barcza ◽
Ádám B. Szirmai ◽
Katalin J. Szántó ◽
Attila Tajti ◽
Péter G. Szalay
Keyword(s):

The ground state intermolecular potential of bimolecular complexes of N-heterocycles is analysed for the impact of different terms of the interaction energy as provided by various, conceptually different theories. Novel combinations with several formulations of the electrostatic, Pauli repulsion, dispersion and other contributions are tested for a good performance at both short- and long-distance sides of the potential energy surface for various alignments of the pyrrole dimer as well as the cytosine-uracil complex. The integration of a DFT/CC density embedding scheme and dispersion terms from the effective fragment potential (EFP) method is found to provide very good agreement with the reference CCSD(T) potential overall, but a QM/MM approach using CHELPG atomic point charges for the electrostatic interaction augmented by EFP dispersion and Pauli repulsion contributions comes also close. Both of these schemes has the advantage of not relying on predefined force fields, rather the interaction parameters can be obtained for the system under study, therefore excellent candidates for ab initio modeling.

2021 ◽
Author(s):
Simon Stephan ◽
Ulrich K. Deiters
Keyword(s):

Equations of state based on intermolecular potentials are often developed about the Lennard-Jones (LJ) potential. Many of such EOS have been proposed in the past. In this work, 20 LJ EOS were examined regarding their performance on Brown’s characteristic curves and characteristic state points. Brown’s characteristic curves are directly related to the virial coefficients at specific state points, which can be computed exactly from the intermolecular potential. Therefore, also the second and third virial coefficient of the LJ fluid were investigated. This approach allows a comparison of available LJ EOS at extreme conditions. Physically based, empirical, and semi-theoretical LJ EOS were examined. Most investigated LJ EOS exhibit some unphysical artifacts.

2021 ◽
Vol 21 (4) ◽
pp. 1063-1078
Author(s):
G. Maroulis ◽
T. Bancewicz
Keyword(s):

Quantum mechanical lineshapes of collision-induced absorption (CIA) at different temperatures are computed for gaseous mixtures of molecular nitrogen and methane using theoretical values for the induced dipole moments and intermolecular potential as input. Comparison with theoretical absorption spectra shows satisfactory agreement. An empirical model of the dipole moment which reproduces the experimental spectra and the first three spectral moments more closely than the fundamental theory, is also presented. Good agreement between computed and experimental absorption lineshapes is obtained when a potential model which is constructed from the thermophysical and transport properties is used.

2021 ◽
Vol 155 (8) ◽
pp. 084302
Author(s):
Qiong Liu ◽
Lu Liu ◽
Feng An ◽
Jing Huang ◽
Yanzi Zhou ◽
...
Keyword(s):

Author(s):
Kentaro Kido
Keyword(s):

2021 ◽
pp. 100114
Author(s):
Mayank Dixit ◽
Joseph Daniel ◽
Keyword(s):

2021 ◽
Vol 154 (23) ◽
pp. 234502
Author(s):
Thijs van Westen
Keyword(s):

2021 ◽
pp. 113124
Author(s):
Manuel Pérez-Molina ◽
Manuel F. Pérez-Polo ◽
Javier Gil Chica ◽
Elena Fernández Varó