howto:gemc
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howto:gemc [2015/07/13 22:16] – [Files required to run GEMC] 130.18.126.132 | howto:gemc [2020/08/21 10:15] – external edit 127.0.0.1 | ||
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- | ==== What is GEMC ==== | + | ==== What is GEMC ?==== |
- | In a Gibbs Ensemble Monte Carlo (GEMC) simulation, 2 boxes are utilized | + | In the most common set up of Gibbs Ensemble Monte Carlo (GEMC) simulation, 2 boxes are utilized |
- | \\ 1)Translations, | + | \\ 1) Translations, |
- | 2)Volume exchanges \\ | + | 2) Volume exchanges \\ |
- | 3)Particle | + | 3) Particle |
- | These particles are swapped between boxes to equilibrate the chemical potential, volume moves equilibrate pressure, and the rest of the moves within a box are performed to maintain thermal equilibrium. The main advantage of the GEMC simulation is that coexisting phases can be observed | + | The particles are swapped between boxes to equilibrate the chemical potential, volume moves equilibrate pressure, and the rest of the moves within a box are performed to maintain thermal equilibrium. The main advantage of the GEMC simulation is that coexisting phases can be simulated |
==== Files required to run GEMC==== | ==== Files required to run GEMC==== | ||
- | In order to run GEMC certain input files are needed; the two main input files for each box {{gemc_nvt_box1.inp.zip}}{{gemc_nvt_box2.inp.zip}}, | + | In order to run GEMC certain input files are needed; the two main input files for each box {{gemc_nvt_box1.inp.zip}}{{gemc_nvt_box2.inp.zip}}, |
==== Sample of input files==== | ==== Sample of input files==== | ||
- | Starting with the input .inp file first, we note that the location of the basis set file, as well as the potential file, is declared( in this case these two files are present in the current working directory). FORCE_EVAL initializes the parameters | + | Starting with the input gemc_nvt_box1.inp file first, we note that the location of the basis set file, as well as the potential file, is declared(in this case these two files are present in the current working directory). |
& | & | ||
METHOD Quickstep | METHOD Quickstep | ||
Line 25: | Line 25: | ||
SCF_GUESS ATOMIC | SCF_GUESS ATOMIC | ||
&END SCF | &END SCF | ||
- | One can increase the SCF iteration | + | One can increase the SCF iterations |
&XC | &XC | ||
& | & | ||
Line 42: | Line 42: | ||
&END XC_GRID | &END XC_GRID | ||
&END XC | &END XC | ||
- | The code snippet below declares the cell and cell ref size. | + | The cell and cell ref of the box 1 in angstorms. |
&CELL | &CELL | ||
ABC 13.7151207699 13.7151207699 13.7151207699 | ABC 13.7151207699 13.7151207699 13.7151207699 | ||
Line 48: | Line 48: | ||
ABC 13.7151207699 13.7151207699 13.7151207699 | ABC 13.7151207699 13.7151207699 13.7151207699 | ||
&END CELL_REF | &END CELL_REF | ||
- | After the above section of code, there is a listing of coordinates for each atom. In addition it should be noted that the condition | ||
- | LBIAS yes | ||
- | must be true, as we pre sample moves in a different potential.The | ||
- | < | ||
- | function determines whether the simulation increment will be in cycles (yes), or in steps (no). | ||
- | The NSTEP feature, shown below | ||
- | NSTEP 5 | ||
- | gives the number of MC cycles in a particular simulation run, and should be adjusted according to the length of the simulation. | ||
- | The line | ||
- | RESTART no | ||
- | should only be set to ' | ||
- | The line | + | After the above section of code, there is a listing of coordinates for each atom. After this, the section |
- | | + | &KIND H |
- | give the file name of the input for Box2 and uses it as a reference such that the two input files are read together. | + | BASIS_SET TZV2P-GTH |
- | ==== Sample of output files==== | + | POTENTIAL GTH-BLYP-q1 |
- | Sample | + | &END KIND |
- | As the input file for Box 1 and Box2 has already been explained above, we will not go into further detail{{gemc_nvt_box1.inp.zip}}{{gemc_nvt_box2.inp.zip}}. We include a topology file, | + | declares the basis set(TZV2P) intended to be used for the simulation. |
+ | The following code | ||
+ | & | ||
+ | PROJECT H2O_MC | ||
+ | RUN_TYPE MC | ||
+ | PRINT_LEVEL LOW | ||
+ | is intended to described the type of run. Consequently, | ||
+ | & | ||
+ | &MC | ||
+ | ENSEMBLE GEMC_NVT | ||
+ | TEMPERATURE 398.0 | ||
+ | IPRINT 1 | ||
+ | LBIAS yes | ||
+ | LSTOP yes | ||
+ | NMOVES 8 | ||
+ | NSWAPMOVES 640 | ||
+ | NSTEP 5 | ||
+ | PRESSURE 1.013 | ||
+ | RESTART no | ||
+ | | ||
+ | | ||
+ | |||
+ | The '' | ||
+ | The line '' | ||
+ | ==== Sample of output files==== | ||
+ | Sample | ||
| BOX 1 | | | BOX 1 | | ||
------------------------------------------------ | ------------------------------------------------ | ||
Line 111: | Line 125: | ||
-------------------------------------------------------------------------------- | -------------------------------------------------------------------------------- | ||
******************************************************************************** | ******************************************************************************** | ||
+ | ------------------------------------------------ | ||
+ | | BOX 2 | | ||
+ | ------------------------------------------------ | ||
+ | ******************************************************************************** | ||
+ | Average Energy [Hartrees]: | ||
+ | Average number of molecules: | ||
+ | Average Volume [angstroms**3]: | ||
+ | | ||
+ | -------------------------------------------------------------------------------- | ||
+ | -------------------------------------------------------------------------------- | ||
+ | Move Data for Molecule Type 1 | ||
+ | -------------------------------------------------------------------------------- | ||
+ | Swap Moves into this box Attempted | ||
+ | 1 0 0.000 | ||
+ | Growths | ||
+ | 1 1 | ||
+ | Total | ||
+ | 1 0 0.000 | ||
+ | ------------------------------------------------------------------------------- | ||
+ | Biased Move Data | ||
+ | -------------------------------------------------------------------------------- | ||
+ | ******************************************************************************** | ||
+ | |||
Additionally, | Additionally, |
howto/gemc.txt · Last modified: 2024/01/03 13:07 by oschuett