CO vibration: Difference between revisions

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 $\hat{x}$ and once in $-\hat{x}$ by 0.02 $\AA$ (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

COvib.tgz

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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@@ Line 1: / Line 1: @@
-*INCAR
+{{Template:At_and_mol - Tutorial}}
- SYSTEM = CO molecule in a box
- ISMEAR = 0   ! Gaussian smearing
- IBRION = 5   ! use the conjugate gradient algorithm
- NFREE = 2    ! central differences
- POTIM = 0.02 ! 0.02 A stepwidth
- NSW = 1      ! ionic steps > 0
-*KPOINTS
+== Task ==
- Gamma-point only
-        ! one k-point
+Calculation of the vibrational frequencies of a CO molecule.
- rec       ! in units of the reciprocal lattice vector
-0 0 1  ! 3 coordinates and weight
+== Input ==
-*POSCAR
+=== {{TAG|POSCAR}} ===
   CO molecule in a box
 .0          ! universal scaling parameters
@@ Line 24: / Line 18: @@
 0 0       F F T  ! first atom
 0 1.143   F F T  ! second atom
+Alternatively, try to fix one of the atoms completely.
+=== {{TAG|INCAR}} ===
+ {{TAGBL|SYSTEM}} = CO molecule in a box
+ {{TAGBL|ISMEAR}} = 0   ! Gaussian smearing
+ {{TAGBL|IBRION}} = 5   ! calculate second derivatives, Hessian matrix, and phonon frequencies
+              ! from finite differences
+ {{TAGBL|NFREE}} = 2    ! central differences
+ {{TAGBL|POTIM}} = 0.02 ! 0.02 A stepwidth
+ {{TAGBL|NSW}} = 1      ! ionic steps > 0
+=== {{FILE|KPOINTS}} ===
+ Gamma-point only
+ Monkhorst Pack
+1 1
+0 0
+== Calculation ==
+*The selected degrees of freedom are displaced once in the direction <math>\hat{x}</math> and once in <math>-\hat{x}</math> by 0.02 <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).
+=== {{TAG|OUTCAR}} ===
+At the end of the {{TAG|OUTCAR}} file the following output should be obtained:
+ SECOND DERIVATIVES (NOT SYMMETRIZED)
+ ------------------------------------
+Z          2Z
+Z  -114.737304  114.737304
+Z   114.458316 -114.458316
+ Eigenvectors and eigenvalues of the dynamical matrix
+ ----------------------------------------------------
+f  =   63.887522 THz   401.417139 2PiTHz 2131.058277 cm-1   264.217647 meV
+             X         Y         Z           dx          dy          dz
+.000000  0.000000  0.000000            0           0   -0.655280
+.000000  0.000000  1.143000            0           0    0.755386
+f/i=    0.038494 THz     0.241864 2PiTHz    1.284016 cm-1     0.159198 meV
+             X         Y         Z           dx          dy          dz
+.000000  0.000000  0.000000            0           0   -0.755386
+.000000  0.000000  1.143000            0           0   -0.655280
 == Download ==
-[http://www.vasp.at/vasp-workshop/examples/1_6_COvib.tgz 1_6_COvib.tgz]
+[[Media:COvib.tgz| COvib.tgz]]
+{{Template:At_and_mol}}
-----
+Back to the [[The_VASP_Manual|main page]].
-[[VASP_example_calculations|To the list of examples]] or to the [[The_VASP_Manual|main page]]
 [[Category:Examples]]