how to discriminate between valence and core electrons objectives check how the core electrons are...
TRANSCRIPT
How to discriminate between valence and core electrons
Objectives
Check how the core electrons are chemically inert
Description of the input file of the ATOM code for an all-electron calculation
ae All-Electron calculation
A title for the job
Chemical symbol of the nucleus
Number of core and valence
orbitals
Principal quantum number
Angular quantum number
Occupation
N 1s2 2s2 2p3
core valence
Exchange-and correlation functionalca Ceperley-Alder (LDA) wi Wigner (LDA)
hl Hedin-Lundqvist (LDA) bh von-Barth-Hedin (LDA)
gl Gunnarson-Lundqvist (LDA)
pb Perdew-Burke-Ernzerhof, PBE (GGA)
rv revPBE (GGA)
rp RPBE, Hammer, Hansen, Norvskov (GGA)
ps PBEsol (GGA)
wc Wu-Cohen (GGA)
bl BLYP Becke-Lee-Yang-Parr (GGA)
am AM05 by Armiento and Mattson (GGA)
vw van der Waals functional
+s if spin (no relativistic)+r if relativistic
How to run an all-electron calculation with ATOM
An explanation of the different files can be found in the ATOM User’s Guide (page 4)
Run the code for different atomic configurations (neutral and ionic)
Neutral configuration: 1s2 2s2 2p3 (N.0.ae.inp)
Ionic configuration +1: 1s2 2s2 2p2 (N.+1.ae.inp)
Ionic configuration +2: 1s2 2s2 2p1 (N.+2.ae.inp)
Ionic configuration +3: 1s2 2s2 2p0 (N.+3.ae.inp)
$../Utils/ae.sh N.0.ae.inp
$../Utils/ae.sh N.1.ae.inp
$../Utils/ae.sh N.2.ae.inp
$../Utils/ae.sh N.3.ae.inp
Plot the angularly integrated (multiplied by 4πr2) core and the charge densities
$ gnuplot –persist charge.N-core.gplot
$ gnuplot –persist charge.N-valence.gplot
Core electrons are chemically inert
All electron calculation for an isolated N atom
Core charge density Valence charge density
Core electrons are chemically inert
All electron calculation for an isolated N atom
Core charge density Valence charge density
Core electrons are chemically inert
All electron calculation for an isolated N atom
Core charge density Valence charge density
Core electrons are chemically inert
All electron calculation for an isolated N atom
Core charge density Valence charge density
Although there are drastic modifications in the valence charge density
The core charge density remains unperturbed
Peak due to the 2s all-electron orbitals of N, (they have a node to be ortogonal with the 1s)
$ cd N.0.ae
$ gnuplot –persist ae.gplot (To generate a figure on the screen using gnuplot)
$ gnuplot ae.gps (To generate a postscript file with the figure)
The radial parts that are plotted are the often called u’s in textbooks
The s-wave functions also go to zero at the origin
To plot the all electron wave functions
To identify the positions of the zero and the extrema
$ vi OUT
For each atomic orbital:•Position of the extrema (r extr)•Position of the zeros (r zero)•Position where the norm is 90 and 99% of the norm of the orbital
Repeating the exercise for Si…
Core electrons are chemically inert
All electron calculation for an isolated Si atom
Core charge density
Core electrons are chemically inert
All electron calculation for an isolated Si atom
Core charge density
Core electrons are chemically inert
All electron calculation for an isolated Si atom
Core charge density
Core electrons are chemically inert
All electron calculation for an isolated Si atom
Core charge density