138 research outputs found
MolMod – an open access database of force fields for molecular simulations of fluids
The MolMod database is presented, which is openly accessible at http://molmod.boltzmann-zuse.de and contains intermolecular force fields for over 150 pure fluids at present. It was developed and is maintained by the Boltzmann-Zuse Society for Computational Molecular Engineering (BZS). The set of molecular models in the MolMod database provides a coherent framework for molecular simulations of fluids. The molecular models in the MolMod database consist of Lennard-Jones interaction sites, point charges, and point dipoles and quadrupoles, which can be equivalently represented by multiple point charges. The force fields can be exported as input files for the simulation programmes ms2 and ls1 mardyn, GROMACS, and LAMMPS. To characterise the semantics associated with the numerical database content, a force field nomenclature is introduced that can also be used in other contexts in materials modelling at the atomistic and mesoscopic levels. The models of the pure substances that are included in the database were generally optimised such as to yield good representations of experimental data of the vapour–liquid equilibrium with a focus on the vapour pressure and the saturated liquid density. In many cases, the models also yield good predictions of caloric, transport, and interfacial properties of the pure fluids. For all models, references to the original works in which they were developed are provided. The models can be used straightforwardly for predictions of properties of fluid mixtures using established combination rules. Input errors are a major source of errors in simulations. The MolMod database contributes to reducing such errors.BMBF, 01IH16008E, Verbundprojekt: TaLPas - Task-basierte Lastverteilung und Auto-Tuning in der PartikelsimulationEC/H2020/694807/EU/Enrichment of Components at Interfaces and Mass Transfer in Fluid Separation Technologies/ENRICOEC/H2020/760907/EU/Virtual Materials Market Place (VIMMP)/VIMM
Bispectrality of Calogero-Moser-Sutherland system
We consider the generalised Calogero-Moser-Sutherland quantum integrable
system associated to the configuration of vectors , which is a union of
the root systems and . We establish the existence of and construct a
suitably defined Baker-Akhiezer function for the system, and we show that it
satisfies bispectrality. We also find two corresponding dual difference
operators of rational Macdonald-Ruijsenaars type in an explicit form.Comment: 25 page
-Analogue of the degree zero part of a rational Cherednik algebra
Inside the double affine Hecke algebra of type
, we define a subalgebra that may be
thought of as a -deformation of the degree zero part of the corresponding
rational Cherednik algebra. We prove that the algebra
is a flat -deformation of the semi-direct
product of the group algebra of the symmetric group
with the image of the Drinfeld-Jimbo quantum group under
the -oscillator (Jordan-Schwinger) representation. We find all the defining
relations and an explicit PBW basis for the algebra
. We describe its centre and establish a double
centraliser property. Further, we develop the connection with integrable
systems introduced by van Diejen, which we also generalise.Comment: 46 page
Contact angle dependence on the fluid-wall dispersive energy
Vapor-liquid menisci of the truncated and shifted Lennard-Jones fluid between
parallel planar walls are investigated by molecular dynamics simulation.
Thereby, the characteristic energy of the unlike dispersive interaction between
fluid molecules and wall atoms is systematically varied to determine its
influence on the contact angle. The temperature is varied as well, covering
most of the range between the triple point temperature and the critical
temperature of the bulk fluid. The transition between obtuse and acute angles
is found to occur at a temperature-independent magnitude of the fluid-wall
dispersive interaction energy. On the basis of the present simulation results,
fluid-wall interaction potentials can be adjusted to contact angle
measurements
Intertwining operator for Calogero-Moser-Sutherland system
We consider generalised Calogero-Moser-Sutherland quantum Hamiltonian
associated with a configuration of vectors on the plane which is a union
of and root systems. The Hamiltonian depends on one parameter.
We find an intertwining operator between and the Calogero-Moser-Sutherland
Hamiltonian for the root system . This gives a quantum integral for of
order 6 in an explicit form thus establishing integrability of .Comment: 24 page
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