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Liquid water: PDOS and Born-Oppenheimer MD
In this exercise, we will look at a more complicated example than in Exercise 1, namely liquid water. We start by computing the PDOS and compare it the single H2O molecules. This time we will have many more orbitals so in order to visualize our results, we will apply a Gaussian broadening to the results. After, we will do a short Born-Oppenheimer MD run and learn how the basic input and output.
======Part 1: PDOS of liquid water
In this part of the exerise we will compute the PDOS. Our model water will contain 64 H2O molecules in a 12 Å box under periodic boundary conditions. The input is very similar to the first exercise, but since we now have a much more coordinates, it is convinient to import them from a separate file. Below is a an example input you can use to perform a single-point calculation extracting the PDOS.
- liquid_water.inp
&GLOBAL PROJECT liquid_water RUN_TYPE ENERGY IOLEVEL LOW &END GLOBAL &FORCE_EVAL METHOD QS &DFT BASIS_SET_FILE_NAME GTH_BASIS_SETS POTENTIAL_FILE_NAME GTH_POTENTIALS LSD 0 &QS METHOD GPW EPS_DEFAULT 1.0E-10 &END QS &SCF MAX_SCF 300 EPS_SCF 1.0E-06 SCF_GUESS ATOMIC &MIXING METHOD DIRECT_P_MIXING ALPHA 0.45 &END MIXING &DIAGONALIZATION ALGORITHM STANDARD &END DIAGONALIZATION &PRINT &RESTART BACKUP_COPIES 0 &END &END PRINT &END SCF &MGRID NGRIDS 4 CUTOFF 300 REL_CUTOFF 60 &END &XC &XC_FUNCTIONAL BLYP &END XC_FUNCTIONAL &END XC &PRINT &PDOS FILENAME ./liquid_water &END PDOS &END PRINT &END DFT &SUBSYS &CELL ABC 12.4170 12.4170 12.4170 ANGLES 90.00 90.00 90.00 &END CELL &TOPOLOGY COORD_FILE_FORMAT XYZ COORD_FILE_NAME liquid_water.xyz CONNECTIVITY OFF &END TOPOLOGY &KIND H BASIS_SET DZVP-GTH POTENTIAL GTH-BLYP-q1 &END KIND &KIND O BASIS_SET DZVP-GTH POTENTIAL GTH-BLYP-q6 &END KIND &END SUBSYS &END FORCE_EVAL &MOTION &GEO_OPT OPTIMIZER BFGS MAX_DR 3.0E-03 MAX_FORCE 4.5E-04 RMS_DR 1.5E-03 RMS_FORCE 3.0E-04 &END &PRINT &RESTART BACKUP_COPIES 0 &END &RESTART_HISTORY OFF &END &END PRINT &END MOTION