Isobaric and Isothermal Molecular Dynamics Simulations of Diatomic Systems |
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Authors: | Vinayak N. Kabadi William A. Steele |
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Affiliation: | 1. Department of Chemical Engineering , North Carolina A&2. T State University , Greensboro , NC , 27411 , U.S.A.;3. Department of Chemistry , The Pennsylvania State University , University Park , PA , 16802 , U.S.A. |
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Abstract: | Abstract Isobaric molecular dynamics simulations were carried out for diatomic systems using different algorithms available in the literature. Two-centered Lennard-Jones potentials with and without quadrupolar interactions were used. Thermodynamic properties obtained from the isobaric algorithms compared very well with those of an equivalent simulation in the microcanonical ensemble; however, some differences were observed when similar comparisons were carried out for dynamic properties. More specifically, the constant pressure constraint affects the translational dynamics of the system because of the non-negligible differences between the momenta and the instantaneous velocities of the molecules. Furthermore, the following studies were carried out using isobaric MD simulations: 1. Low temperature spontaneous FCC-orthorhombic (and vice versa) transition of a diatomic system with quadrupolar interactions as a function of the molecular bond length. 2. Effect of quadrupolar interaction on isobaric melting of a model diatomic system. 3. Effect of pressure on melting properties of a model diatomic system with quadrupolar interactions. |
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Keywords: | Diatomic systems isobaric simulations melting molecular dynamics quadrupolar interactions |
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