CO vibration: Difference between revisions
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{{Template:At_and_mol}} | {{Template:At_and_mol - Tutorial}} | ||
== Task == | == Task == | ||
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{{TAGBL|SYSTEM}} = CO molecule in a box | {{TAGBL|SYSTEM}} = CO molecule in a box | ||
{{TAGBL|ISMEAR}} = 0 ! Gaussian smearing | {{TAGBL|ISMEAR}} = 0 ! Gaussian smearing | ||
{{TAGBL|IBRION}} = 5 ! | {{TAGBL|IBRION}} = 5 ! calculate second derivatives, Hessian matrix, and phonon frequencies | ||
! from finite differences | |||
{{TAGBL|NFREE}} = 2 ! central differences | {{TAGBL|NFREE}} = 2 ! central differences | ||
{{TAGBL|POTIM}} = 0.02 ! 0.02 A stepwidth | {{TAGBL|POTIM}} = 0.02 ! 0.02 A stepwidth | ||
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== Calculation == | == Calculation == | ||
*The selected degrees of freedom are displaced once in the direction <math>\hat{x}</math> and once in <math>-\hat{x}</math> by 0. | *The selected degrees of freedom are displaced once in the direction <math>\hat{x}</math> and once in <math>-\hat{x}</math> by 0.02 <math>\AA</math> ({{TAG|POTIM}}). | ||
*In the present case this makes 4 displacements plus the equilibrium positions (i.e. a total of five ionic configurations). | *In the present case this makes 4 displacements plus the equilibrium positions (i.e. a total of five ionic configurations). | ||
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== Download == | == Download == | ||
[ | [[Media:COvib.tgz| COvib.tgz]] | ||
{{Template:At_and_mol}} | |||
Back to the [[The_VASP_Manual|main page]]. | |||
[[Category:Examples]] | [[Category:Examples]] | ||
Latest revision as of 11:00, 13 November 2019
Overview > O atom > O atom spinpolarized > O atom spinpolarized low symmetry > O dimer > CO > CO vibration > CO partial DOS > H2O >
H2O vibration > H2O molecular dynamics > Further things to try > List of tutorials
Task
Calculation of the vibrational frequencies of a CO molecule.
Input
POSCAR
CO molecule in a box 1.0 ! universal scaling parameters 8.0 0.0 0.0 ! lattice vector a(1) 0.0 8.0 0.0 ! lattice vector a(2) 0.0 0.0 8.0 ! lattice vector a(3) 1 1 ! number of atoms for each species sel ! selective degrees of freedom are changed cart ! positions in cartesian coordinates 0 0 0 F F T ! first atom 0 0 1.143 F F T ! second atom
Alternatively, try to fix one of the atoms completely.
INCAR
SYSTEM = CO molecule in a box ISMEAR = 0 ! Gaussian smearing IBRION = 5 ! calculate second derivatives, Hessian matrix, and phonon frequencies ! from finite differences NFREE = 2 ! central differences POTIM = 0.02 ! 0.02 A stepwidth NSW = 1 ! ionic steps > 0
KPOINTS
Gamma-point only 0 Monkhorst Pack 1 1 1 0 0 0
Calculation
- The selected degrees of freedom are displaced once in the direction and once in by 0.02 (POTIM).
- In the present case this makes 4 displacements plus the equilibrium positions (i.e. a total of five ionic configurations).
OUTCAR
At the end of the OUTCAR file the following output should be obtained:
SECOND DERIVATIVES (NOT SYMMETRIZED)
------------------------------------
1Z 2Z
1Z -114.737304 114.737304
2Z 114.458316 -114.458316
Eigenvectors and eigenvalues of the dynamical matrix
----------------------------------------------------
1 f = 63.887522 THz 401.417139 2PiTHz 2131.058277 cm-1 264.217647 meV
X Y Z dx dy dz
0.000000 0.000000 0.000000 0 0 -0.655280
0.000000 0.000000 1.143000 0 0 0.755386
2 f/i= 0.038494 THz 0.241864 2PiTHz 1.284016 cm-1 0.159198 meV
X Y Z dx dy dz
0.000000 0.000000 0.000000 0 0 -0.755386
0.000000 0.000000 1.143000 0 0 -0.655280
Download
Overview > O atom > O atom spinpolarized > O atom spinpolarized low symmetry > O dimer > CO > CO vibration > CO partial DOS > H2O >
H2O vibration > H2O molecular dynamics > Further things to try > List of tutorials
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