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Title: First principles study of pressure induced polymorphic phase transition in KNO{sub 3}

We report the structural, elastic, electronic, and vibrational properties of polymorphic phases II and III of KNO{sub 3} based on density functional theory (DFT). Using semi-empirical dispersion correction (DFT-D2) method, we predicted the correct thermodynamic ground state of KNO{sub 3} and the obtained ground state properties of the polymorphs are in good agreement with the experiments. We further used this method to calculate the elastic constants, IR and Raman spectra, vibrational frequencies and their assignment of these polymorphs. The calculated Tran Blaha-modified Becke Johnson (TB-mBJ) electronic structure shows that both the polymorphic phases are direct band gap insulators with mixed ionic and covalent bonding. Also the TB-mBJ band gaps are improved over standard DFT functionals which are comparable with the available experiments.
Authors:
;  [1]
  1. Advanced Centre of Research in High Energy Materials (ACRHEM), University of Hyderabad, Prof. C. R. Rao Road, Gachibowli, Hyderabad-500 046, Telangana (India)
Publication Date:
OSTI Identifier:
22490179
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1665; Journal Issue: 1; Conference: 59. DAE solid state physics symposium 2014, Tamilnadu (India), 16-20 Dec 2014; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHEMICAL BONDS; COMPARATIVE EVALUATIONS; CORRECTIONS; COVALENCE; DENSITY FUNCTIONAL METHOD; ELECTRONIC STRUCTURE; ENERGY GAP; GROUND STATES; INFRARED SPECTRA; PHASE TRANSFORMATIONS; POTASSIUM NITRATES; RAMAN SPECTRA