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231223s2004 xx ||||| 00| ||eng c |
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|a (DE-627)NLM150506953
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|a (NLM)15376250
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|a DE-627
|b ger
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|e rakwb
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|a eng
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|a Zicovich-Wilson, C M
|e verfasserin
|4 aut
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|a Calculation of the vibration frequencies of alpha-quartz
|b the effect of Hamiltonian and basis set
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|c 2004
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|a Text
|b txt
|2 rdacontent
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|a ohne Hilfsmittel zu benutzen
|b n
|2 rdamedia
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|a Band
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|2 rdacarrier
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|a Date Completed 22.11.2004
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|a Date Revised 29.09.2004
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|a published: Print
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|a Citation Status PubMed-not-MEDLINE
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|a Copyright 2004 Wiley Periodicals, Inc.
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|a The central-zone vibrational spectrum of alpha-quartz (SiO2) is calculated by building the Hessian matrix numerically from the analytical gradients of the energy with respect to the atomic coordinates. The nonanalytical part is obtained with a finite field supercell approach for the high-frequency dielectric constant and a Wannier function scheme for the evaluation of Born charges. The results obtained with four different Hamiltonians, namely Hartree-Fock, DFT in its local (LDA) and nonlocal gradient corrected (PBE) approximation, and hybrid B3LYP, are discussed, showing that B3LYP performs far better than LDA and PBE, which in turn provide better results than HF, as the mean absolute difference from experimental frequencies is 6, 18, 21, and 44 cm(-1), respectively, when a split valence basis set containing two sets of polarization functions is used. For the LDA results, comparison is possible with previous calculations based on the Density Functional Perturbation Theory and usage of a plane-wave basis set. The effects associated with the use of basis sets of increasing size are also investigated. It turns out that a split valence plus a single set of d polarization functions provides frequencies that differ from the ones obtained with a double set of d functions and a set of f functions on all atoms by on average less than 5 cm(-1)
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|a Journal Article
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|a Pascale, F
|e verfasserin
|4 aut
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|a Roetti, C
|e verfasserin
|4 aut
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|a Saunders, V R
|e verfasserin
|4 aut
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|a Orlando, R
|e verfasserin
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|a Dovesi, R
|e verfasserin
|4 aut
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|i Enthalten in
|t Journal of computational chemistry
|d 1984
|g 25(2004), 15 vom: 30. Nov., Seite 1873-81
|w (DE-627)NLM098138448
|x 1096-987X
|7 nnns
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| 773 |
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|g volume:25
|g year:2004
|g number:15
|g day:30
|g month:11
|g pages:1873-81
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|a GBV_USEFLAG_A
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|a GBV_ILN_350
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|a AR
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|d 25
|j 2004
|e 15
|b 30
|c 11
|h 1873-81
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