XPS: Difference between revisions

Latest revision as of 17:35, 11 January 2022

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General workflow[edit]

An XPS calculation is a single ionic step calculation, and involves the explicit computation of core levels for one selected atom in the POSCAR.

For a converged structure select a single atom for which the core levels shifts will be calculated. Let us suppose that you are interested in the second Pd atom in this POSCAR:

(...)
 Pd   In     O 
 4    80    119 
(...)

The atom(s) for which the XPS will be calculated should be separated:

(...)
 Pd  Pd  Pd   In     O 
 1   1   2    80    119 
(...)

Create two separate subdirectories, (for example ./xps0 and ./xps1) and copy the modified POSCAR to both.

Create a new pseudopotential file.

Copy the KPOINTS and INCAR files of your typical setup to "xps0" and "xps1". Dipole corrections and ionic movements must be turned off. ISPIN must be turned to 2. It is recommended to deactivate vdW. Comment all parallelization flags to use the default:

  ISPIN   =  2       #
# LDIPOL  =  F  
# IDIPOL  =  3  
  IBRION  = -1  
  NSW     =  1

In "xps0", insert tags for XPS calculation to INCAR:

  ICORELEVEL = 1     # State before excitation XPS.
# CLNT = 2           # species in POSCAR, second in the example.
# CLN  = 3           # main quantum number (3d ==> N=3). 
# CLL  = 2           # l quantum number; s=0, p=1, d=2,...  
# CLZ  = 1           # number of electrons to be displaced. Do not use 0.5.  
  NELECT=            # Put the same number of electrons from a normal calculation.

After the job is completed:

 grep TOTEN OUTCAR | tail -n 1 # let's call this value E0

In parallel, insert tags for XPS calculation to INCAR of xps1:

  ICORELEVEL = 2     # final state approximation (fss, with electron exitation).
  CLNT = 2           # species in POSCAR, second in the example.
  CLN  = 3           # main quantum number (3d ==> N=3).
  CLL  = 2           # l quantum number; s=0, p=1, d=2,...  
  CLZ  = 1           # number of electrons to be displaced. Do not use 0.5.    
  NELECT=            # For fss, put an additional electron. For iss, don't.

After the job is completed:

 grep TOTEN OUTCAR | tail -n 1 # let's call this value E1

The XPS shift (Exps) can be calculated as:

 Exps = E1 - E0

Additional information[edit]

Media:Overview.pdf (by Nathan)

@@ Line 1: / Line 1: @@
+go back to [[Main Page]], [[Group Pages]], [[Núria López and Group]]
 ==General workflow==
-in preparation (currently just a sketch)
+An XPS calculation is a single ionic step calculation, and involves the explicit computation of core levels for '''one''' selected atom in the POSCAR.
+* For a converged structure select a single atom for which the core levels shifts will be calculated. Let us suppose that you are interested in the second Pd atom in this POSCAR:
+ (...)
+  Pd   In     O
+    80    119
+ (...)
+* The atom(s) for which the XPS will be calculated should be separated:
+ (...)
+  Pd  '''Pd'''  Pd   In     O
+   '''1'''   2    80    119
+ (...)
+* Create two separate subdirectories, (for example ./xps0 and ./xps1) and copy the modified POSCAR to both.
+* Create a new pseudopotential file.
+* Copy the KPOINTS and INCAR files of your typical setup to "xps0" and "xps1". Dipole corrections and ionic movements must be turned off. ISPIN must be turned to 2. It is recommended to deactivate vdW. Comment all parallelization flags to use the default:
+   ISPIN   =  2       #
+ # LDIPOL  =  F
+ # IDIPOL  =  3
+   IBRION  = -1
+   NSW     =  1
+* In "xps0", insert tags for XPS calculation to INCAR:
+   ICORELEVEL = 1     # State before excitation XPS.
+ # CLNT = 2           # species in POSCAR, second in the example.
+ # CLN  = 3           # main quantum number (3d ==> N=3).
+ # CLL  = 2           # l quantum number; s=0, p=1, d=2,...
+ # CLZ  = 1           # number of electrons to be displaced. Do not use 0.5.
+   NELECT=            # Put the same number of electrons from a normal calculation.
+* After the job is completed:
+  grep TOTEN OUTCAR | tail -n 1 # let's call this value E0
+* In parallel, insert tags for XPS calculation to INCAR of xps1:
+   ICORELEVEL = 2     # final state approximation (fss, with electron exitation).
+   CLNT = 2           # species in POSCAR, second in the example.
+   CLN  = 3           # main quantum number (3d ==> N=3).
+   CLL  = 2           # l quantum number; s=0, p=1, d=2,...
+   CLZ  = 1           # number of electrons to be displaced. Do not use 0.5.
+   NELECT=            # For fss, put an additional electron. For iss, don't.
+* After the job is completed:
+  grep TOTEN OUTCAR | tail -n 1 # let's call this value E1
+* The XPS shift (Exps) can be calculated as:
+  Exps = E1 - E0
-* For a convergeed structure select a single atom for which the core levels shifts will be calculated (link to gli script to be added)
-* Insert tags for XPS calculation
-    ICORELEVEL = 2     # final state XPS
+==Additional information==
-    CLNT = 3           # atom type POSCAR
+[[Media:Overview.pdf]] (by Nathan)
-    CLN = 3            # main quantum number
-    CLL = 2            # l quantum number
-    CLZ = 1            # 1 or 0.5. Final state XPS = 1
-* Import chi.dat.
-* Select chi(k) as data type.
-* Click in "replot".
-* Select the element and edge. (i.e., Pd, K-edge).
-* Edit k-range [3.0;14.0], dK=1.
-* Select plotting k-weights: 3.
-* Apply a forward Fourier transform.
-* Change plot to R-space, Magnitude-Magnitude. Select and unselect "real part" to update the graph. This will generate a plot |chi(R)| in Å^(-4) as a function of the radial distance in Å.
-* To change the units of chi(R), change the k-weights.
-* In the main window, clic on file > save current group as > chi(R).
-* Save the file as .dat inside your Windows virtual machine. Then move to the shared folder to do the analysis.
-* You can now do a fancy plot in Origin, showing the chi(R) data you got from Athena.

XPS: Difference between revisions

Latest revision as of 17:35, 11 January 2022

General workflow[edit]

Additional information[edit]

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