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Time‐dependent density functional theory calculation of van der Waals coefficient of potassium clusters
Author(s) -
Banerjee Arup,
Chakrabarti Aparna,
Ghanty Tapan K.
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.21933
Subject(s) - van der waals force , jellium , chemistry , density functional theory , dipole , ab initio , dispersion (optics) , van der waals radius , atomic physics , local density approximation , atom (system on chip) , molecular physics , computational chemistry , physics , quantum mechanics , molecule , organic chemistry , computer science , metal , embedded system
We employ all‐electron ab initio time‐dependent density functional theory (DFT)‐based method to calculate the long range dipole–dipole dispersion coefficient (van der Waals coefficient) C 6 of potassium atom clusters (K n ) containing even number of atoms, n ranging from 2 to 20. The dispersion coefficients are obtained via Casimir–Polder relation. The calculations are carried out with the asymptotically correct statistical average of orbital potential and compared with the results obtained using Vosko–Wilk–Nusair representation of exchange‐correlation potential within local density approximation. We report the dispersion coefficients between clusters of sodium and potassium atoms as well. The present results have been compared with the available jellium‐based model and other DFT results in the literature. We also study the relationship between volume of the cluster and the C 6 for K clusters. It is observed that the C 6 scales as square of the volume. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009