# Open SourceMolecular Dynamics

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exercises:2017_ethz_mmm:hfx_h2ion

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 — exercises:2017_ethz_mmm:hfx_h2ion [2017/02/22 10:01] (current) Line 1: Line 1: + ====== Hartree-Fock exchange for the dihydrogen cation ====== + The goal of this exercise is to calculate the dissociate enery profile of the [[wp>​Dihydrogen_cation|dihydrogen cation]] $H_2^+$. + The curve should be record for three different fractions of Hartree-Fock exchange: + * 0% HF exchange, 100% PBE exchange + * 50% HF exchange, 50% PBE exchange + * 100% HF exchange, 0% PBE exchange + + ===== Questions ===== + * Report the dissociation curve for the $H^+_2$ ion, for the three fractions of Hartree-Fock exchange employed. + + ===== Required Files ===== + + ==== Input File ==== + ​ + &GLOBAL + PROJECT H2ion + RUN_TYPE ENERGY + &END GLOBAL + + &​FORCE_EVAL + METHOD Quickstep + &DFT + ! data-files for basis-set and pseudo-potentials + BASIS_SET_FILE_NAME HFX_BASIS  ​ + POTENTIAL_FILE_NAME POTENTIAL + ​ + &​MGRID ​             ! resolution of finest grid, higher values give more accurate results + CUTOFF 400 + &END MGRID + + &​POISSON ​           ! Non periodic calculation needs Poisson solver + PERIODIC NONE + PSOLVER ​ WAVELET + &END POISSON + ​ + &​SCF ​                ! need to achieve SCF-convergence at large H-H distances + &OT + PRECONDITIONER FULL_ALL + &END OT + &END SCF + ​ + CHARGE 1             ! H2 cation is positively charged... + MULTIPLICITY 2       ! ...and therefore in a doublet spin state... + LSD                  ! ...so that we have to run an unrestricted Kohn-Sham calculation + ​ + &​XC ​                 ! Exchange and Correlation settings + &​XC_FUNCTIONAL + &PBE + SCALE_X 0.5   ! amount of PBE eXchange (vary consistently with the HF/​FRACTION) + SCALE_C 1.0    ! amount of PBE Correlation. DO NOT VARY!!!!!! + &END + &END XC_FUNCTIONAL + &HF + FRACTION 0.5    ! amount of HF eXchange (vary consistently with PBE/​SCALE_X) + &​SCREENING + EPS_SCHWARZ 1.0E-10 + &END + &END HF + &END XC + &END DFT + + &SUBSYS + &​TOPOLOGY + &​CENTER_COORDINATES ​ ! keep atoms away from box borders, would confuse Poisson solver + &END + &END + &CELL + ABC 15.0 15.0 15.0 + PERIODIC NONE  ! Non periodic calculation. ​ + &END CELL + &COORD + ​H ​   0.0   ​0.0 ​  0.0 + ​H ​   0.42  0.0   ​0.0 ​ ! vary H-H distance to record dissociation profile + &END COORD + &KIND H + BASIS_SET DZVP-GTH + POTENTIAL GTH-PBE-q1 + &END KIND + &END SUBSYS + &END FORCE_EVAL + ​ + + ==== Basis Set ==== + ​ + H DZVP-GTH + 3 + 1  0  0  3  1 + 8.3744350009 ​ -0.0283380461 ​ + 1.8058681460 ​ -0.1333810052 ​ + 0.4852528328 ​ -0.3995676063 ​ + 1  0  0  1  1 + 0.1658236932 ​  ​1.0000000000 + 2  1  1  1  1 + 0.7270000000 ​  ​1.0000000000 + # + C DZVP-GTH + 3 + 2  0  1  3  1  1 + 4.3362376436 ​  ​0.1490797872 ​ -0.0878123619 + 1.2881838513 ​ -0.0292640031 ​ -0.2775560300 + 0.4037767149 ​ -0.6882040510 ​ -0.4712295093 + 2  0  1  1  1  1 + 0.1187877657 ​  ​1.0000000000 ​  ​1.0000000000 + 3  2  2  1  1 + 0.5500000000 ​  ​1.0000000000 + ​ + + ==== Pseudo Potential ==== + ​ + H GTH-PBE-q1 + 1 + ​0.20000000 ​   2    -4.17890044 ​    ​0.72446331 + 0 + # + C GTH-PBE-q4 + 2    2 + ​0.33847124 ​   2    -8.80367398 ​    ​1.33921085 + 2 + ​0.30257575 ​   1     ​9.62248665 + ​0.29150694 ​   0 +  ​     ​ 