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exercises:2015_pitt:hfx [2015/03/05 09:02]
vondele [4rd task : introduce ADMM]
exercises:2015_pitt:hfx [2015/03/05 11:20] (current)
vondele
Line 172: Line 172:
 Run the input, what's the ''​HOMO - LUMO gap''​ ? Run the input, what's the ''​HOMO - LUMO gap''​ ?
  
 +===== Chasing charge localization in liquid water =====
 +
 +The combination of truncated exchange and ADMM results in the most effective way to run AIMD with hybrid functionals. In some systems the difference between GGA DFT and hybrids is very large. One such systems is liquid water after ionization (i.e. charge +1), where only with hybrids the expected species (OH radicals) are formed. See [[doi>​10.1063/​1.3664746]].
 +
 +==== 5th task : ionized water ====
 +
 +<​note>​This task is optional, and can be done near the end if time is available. </​note>​
 +
 +adapt the admm input for water to reflect the ionized state:
 +<​code>​
 +    ! Charge and multiplicity
 +    LSD
 +    CHARGE 1
 +    MULTIPLICITY 2
 +</​code>​
 +because the system is electronically very difficult initially, we'll reduce the convergence threshold ''​EPS_SCF 1.0E-5''​ (twice).
 +
 +Note that the ''​WFN_RESTART_FILE_NAME''​ must point to a GGA calculation of the same charge and multiplicity (do this calculations first).
 +
 +Run single point energy calculations varying the fraction of exchange from 0.25 to 0.50,  does the mulliken spin population reproduce Fig. 2 in [[doi>​10.1021/​ct1002225]] ?
 +
 +For the fraction 0.5, run AIMD for about 50-100fs (if time permits), what happens with the water molecule on which the spin was localized ? Do you results agree with [[doi>​10.1063/​1.3664746]] ?
  
 ===== Required files ===== ===== Required files =====
exercises/2015_pitt/hfx.txt ยท Last modified: 2015/03/05 11:20 by vondele