Free Atoms in DFT

Hands-On Instructions for the FHI-aims Code 


Contents 

1 Theoretical background 1 
2 A quick tour of the technical details 2 
2.1 Basis set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 
2.2 Numerical integration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 
2.3 Generalized eigenvalue problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.4 Electrostatic (Hartree) potential of the electrons . . . . . . . . . . . . . . . . . . 3 2.5 Self-consistency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 
3 Single atom calculation with FHI-aims — Step by step 4 
3.1 Task preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 
3.2 geometry.in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 
3.3 control.in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 
3.4 The basis set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 
4 Finally: The Hydrogen Atom 7 
4.1 Energy and Eigenvalues for the Minimal Basis in Hartree-Fock Theory . .  . 7 
4.2 Changing to the Local-Density Approximation . . . . . . . . . . . . . . . . . . . 8 4.3 Converging the basis set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 
4.4 Plotting the density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 
4.5 Visualizing the radial distribution function . . . . . . . . . . . . . . . . . . . . . . 10 5 The Silicon Atom 10


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http://aims.pratt.duke.edu/sites/aims.pratt.duke.edu/files/Exercise_9_instructions_0.pdf