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exercises:2014_ethz_mmm:tio2_gap [2014/04/10 15:25]
oschuett
exercises:2014_ethz_mmm:tio2_gap [2014/10/15 13:32] (current)
oschuett
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 ====== TiO$_2$ Band Gap as a function of %hfx ====== ====== TiO$_2$ Band Gap as a function of %hfx ======
  
-One problem with standard DFT is that correlation effects can lead to errors in evaluating certain system properties, such as the band gap of semiconductors. More information can be found here: +One problem with standard DFT is that correlation effects can lead to errors in evaluating certain system properties, such as the band gap of semiconductors. More information can be found here: [[doi>10.1126/science.1158722]]
-<note todo> +
-LINK? +
-</note>+
  
 A common approach to correct for electronic self-interaction is the //ad hoc// mixing of a fraction of the exact Hartree-Fock exchange. The goal of this exercise is to identify the needed amount of exact Hartree-Fock exchange (%hfx) to correctly reproduce the anatase TiO$_2$ experimental band gap (3.2 eV). To do so, you will need to run at least 4 single point calculations on bulk TiO$_2$ with varying amount of exact exchange. ​ A common approach to correct for electronic self-interaction is the //ad hoc// mixing of a fraction of the exact Hartree-Fock exchange. The goal of this exercise is to identify the needed amount of exact Hartree-Fock exchange (%hfx) to correctly reproduce the anatase TiO$_2$ experimental band gap (3.2 eV). To do so, you will need to run at least 4 single point calculations on bulk TiO$_2$ with varying amount of exact exchange. ​
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 <note tip> <note tip>
-Hybrid calculations can be fairly expensive, because they scale with $\mathcal{O}(N^4)$. Therefore, you should run these jobs on 16 nodes. +Hybrid calculations can be fairly expensive, because they scale with $\mathcal{O}(N^4)$. Therefore, you should run these jobs on 16 nodes. To further decrease the cost of the calculation,​ you can restart from previously generated wave-function files (*-RESTART.wfn). At the end of this exercise, a readily optimized wave-function is provided to you.
-</​note>​ +
- +
-<note tip> +
-To further decrease the cost of the calculation,​ you can restart from previously generated wave-function files (*-RESTART.wfn). At the end of this exercise, a readily optimized wave-function is provided to you.+
 </​note>​ </​note>​
  
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 ===== Required files ===== ===== Required files =====
-  * file with truncation parameters: ​{{:exercise:t_c_g.dat.gz|}} +==== Parameters for Truncated Coulomb Potential ==== 
-  ​Restart wave-functionuseful to speed up calculations: ​{{:exercise:tio2_pbe-restart.wfn.gz|}}+{{t_c_g.dat.gz| ​Download here}} 
 +  ​ 
 +==== Restart wave-function ​==== 
 + This is useful to speed up the calculation 
 + {{tio2_pbe-restart.wfn.gz| ​Download here}}
  
 <​note>​ These files are compressed with gzip. To unpack them run: <​note>​ These files are compressed with gzip. To unpack them run:
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 </​note>​ </​note>​
  
-  * input file+==== Input File ====
 <code - anatase_25hfx.inp>​ <code - anatase_25hfx.inp>​
  
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 </​code>​ </​code>​
  
- +==== Basis Set ==== 
-  * basis set +<code - BASIS_TiO>​
-<code - BASIS_TiO >+
  
 # O # O
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 </​code>​ </​code>​
  
-  * potential+==== Pseudo-Potential ====
 <code - POTENTIALS_TiO>​ <code - POTENTIALS_TiO>​
 # #
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 </​code>​ </​code>​
  
-  * anatase *.cif file (crystallographic information file = anatse crystal structure)+==== Anatse Crystal Structure ==== 
 + 
 +''​.cif''​ = crystallographic information file
  
-<code - tio.cif >+<code - tio.cif>
 #​====================================================================== #​======================================================================
  
exercises/2014_ethz_mmm/tio2_gap.1397143552.txt.gz · Last modified: 2014/04/10 15:25 by oschuett