aim input variables¶

This document lists and provides the description of the name (keywords) of the aim input variables to be used in the input file for the aim executable.

atom¶

Mnemonics: index of ATOM
Variable type: integer
Dimensions: scalar
Default value: 1

Test list (click to open). Very frequently used, [5/5] in all aim tests, [0/0] in aim tutorials

Index of the investigated atom.

Variable type: real
Dimensions: scalar
Default value: 1.0

Test list (click to open). Moderately used, [⅖] in all aim tests, [0/0] in aim tutorials

A first estimation of the Bader radius (not too important - it is used only two times)

coff1¶

Mnemonics: COeFFicient 1
Variable type: real
Dimensions: scalar
Default value: 0.98

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

See the input variable ratmin@aim.

coff2¶

Mnemonics: COeFFicient 2
Variable type: real
Dimensions: scalar
Default value: 0.95

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

See the input variable ratmin@aim.

crit¶

Mnemonics: computation of CRITical points
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Very frequently used, [5/5] in all aim tests, [0/0] in aim tutorials

Drives the computation of critical points.

• [0] not
• [-1] reading from the file root’‘.crit
• [1] calculated (simplified version)
• [2] calculated (standard version - recommended)
• [3] calculated (the original version)

The original version searches all critical points (CPs) starting from the center between two and three atoms (atom - neighbor(s)) by Newton-Raphson algorithm - without tests (not recommended) - don’t use together with surface analysis !

The simplified and standard versions search CP(3,-1) starting from the center of the pairs~atom-neighbor; then CP(3,1) from the center between two CP(3,-1) and finally CP(3,3) from the center between two CP(3,1). The robust Popeliers’s algorithm is used. The difference between the two is based in the fact that the standard version makes the test if the CP is really on the Bader surface of the calculated atom for each CP, while the simplified version does this only for CP(3,-1). When CP analysis is rather fast (with respect to surface determination), 2 is recommended. In all cases the number of neighbors considered is limited by distance cutoff (variable maxatd@aim)

denout¶

Mnemonics: electronic DENsity OUTput
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

Output of the electronic density. The specification of the line (plane) in the real space must be given in the input variable vpts@aim and grid in ngrid@aim. It is also possible to get only the valence density or the core density (see dltyp@aim).

• 0, no output
• 1, 1D distribution
• 2, 2D distribution

dltyp¶

Mnemonics: Density or Laplacian TYP output
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

Specification of the contribution of the electronic density corresponding to the density and/or laplacian output (see denout@aim and lapout@aim)

• 0, total electronic density
• 1, only the valence density
• 2, only the core density

dpclim¶

Mnemonics: DPCLIM
Variable type: real
Dimensions: scalar
Default value: 1.d-2

Test list (click to open). Moderately used, [⅕] in all aim tests, [0/0] in aim tutorials

If two “numerically different” critical points are separated by less than dpclim , they are considered to be the same critical point. This often happens because of numerical inaccuracies : one CP might be “seen” by two different finite elements. The default should be OK when the ecut is quite large, on the order of 60 Hartree. For less accurate calculations of the density, increase the default value to 5.d-2, let’s say.

foldep¶

Variable type: real
Dimensions: (3)
Default value: 3*0.0

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

Needed in the case follow=1 only. Defines the starting point.

follow¶

Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Very frequently used, [5/5] in all aim tests, [0/0] in aim tutorials

Follow the gradient path to the corresponding atom starting from the position specified in the input variable foldep.

folstp¶

Variable type: real
Dimensions: scalar
Default value: 0.5

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

The first step for following the gradient path.

gpsurf¶

Mnemonics: GraPhic output for the bader SURFace
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Very frequently used, [5/5] in all aim tests, [0/0] in aim tutorials

Drives the graphic output (gnuplot script) of the irreducible part of the calculated Bader surface.

• 0, not output
• 1, output

inpt¶

Mnemonics: numer of INtegration PoinTs
Variable type: integer
Dimensions: scalar
Default value: 100

Test list (click to open). Very frequently used, [5/5] in all aim tests, [0/0] in aim tutorials

Number of radial points used for integration of the Bader charge (not too sensitive).

irho¶

Mnemonics: Integration of the charge density RHO
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Very frequently used, [5/5] in all aim tests, [0/0] in aim tutorials

Drives the integration of the charge of the Bader atom.

• 0, not calculated
• 1, calculated (usual mode)

ivol¶

Mnemonics: Integration of the VOLume
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Moderately used, [⅕] in all aim tests, [0/0] in aim tutorials

Drives the integration of the volume of the Bader atom.

• 0, not calculated
• 1, calculated

lapout¶

Mnemonics: electronic density LAPlacian OUTput
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

Output of the laplacian of electronic density. The specification of the line (plane) in the real space must be given in the input variable vpts and grid in ngrid. It is also possible to get only the valence density or the core density (see dltyp).

• 0, no output
• 1, 1D distribution
• 2, 2D distribution

Variable type: real
Dimensions: scalar
Default value: 1.d-12

Test list (click to open). Very frequently used, [⅗] in all aim tests, [0/0] in aim tutorials

The search for one particular CP is decided to be successful when either the norm of the gradient of the electron density is smaller than lgrad or when the length of the planned search step is smaller than lstep. If the number of search step becomes larger than an internal limit (presently set to 100), one will allow a weaker criteria for satisfaction, based on lgrad2 and lstep2. If the internal limit is reached, and the criteria on lgrad2 and lstep2 are not satisfied, then the searching procedure continues with the next seed.

Variable type: real
Dimensions: scalar
Default value: 1.d-5

Test list (click to open). Very frequently used, [⅗] in all aim tests, [0/0] in aim tutorials

Determines the criterion for deciding that a CP has been found. See lgrad for more details.

lstep¶

Mnemonics: Length of the planned search STEP
Variable type: real
Dimensions: scalar
Default value: 1.d-10

Test list (click to open). Very frequently used, [⅗] in all aim tests, [0/0] in aim tutorials

Determines the criterion for deciding a CP has been found. See lgrad for more details.

lstep2¶

Mnemonics: Length of the planned search STEP 2
Variable type: real
Dimensions: scalar
Default value: 1.d-5

Test list (click to open). Very frequently used, [⅗] in all aim tests, [0/0] in aim tutorials

Determines the criterion for deciding that a CP has been found. See lgrad for more details.

maxatd¶

Mnemonics: MAXimal ATomic Distance
Variable type: real
Dimensions: scalar
Default value: 10.0

Test list (click to open). Very frequently used, [5/5] in all aim tests, [0/0] in aim tutorials

Atoms within this maximal distance are considered in order to start the search of a CP.

Note that the supercell, determined by nsa, nsb, and nsc might be too small to actually lead to the consideration of all the desired atoms.

maxcpd¶

Mnemonics: MAXimal CP Distance
Variable type: real
Dimensions: scalar
Default value: 5.0

Test list (click to open). Very frequently used, [⅘] in all aim tests, [0/0] in aim tutorials

The CPs are searched for within this maximal distance.

Note that the supercell, determined by nsa, nsb, and nsc might be too small to actually lead to the consideration of all the critical points.

ngrid¶

Mnemonics: Number of GRID points
Variable type: integer
Dimensions: (2)
Default value: 2*30

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

Defines the grid in real space, for the density and laplacian outputs, governed by denout and lapout.

nphi¶

Mnemonics: Number of PHI angle
Variable type: integer
Dimensions: scalar
Default value: 48

Test list (click to open). Very frequently used, [5/5] in all aim tests, [0/0] in aim tutorials

With ntheta, this variable defines the angular grid for the integration within the Bader volume, in particular, the number of phi angles, to be used between phimin and phimax. When the difference between these two variables is 2 $\pi$, the recommended value of nphi is 48. When it is $\pi$ (for symmetry reasons), the recommended value is 32. When it is $\pi$/2 (for symmetry reasons), the recommended value is 20.

nsa¶

Mnemonics: Number of Supercell points in direction A
Variable type: integer
Dimensions: scalar
Default value: 3

Test list (click to open). Very frequently used, [⅘] in all aim tests, [0/0] in aim tutorials

These variables define a “supercell”, from the primitive cell repeated along each primitive direction. This supercell is build as follows :

  do isa=-nsa,nsa
do isb=-nsb,nsb
do isc=-nsc,nsc
-> here, the cell is translated by the vector
-> (isa,isb,isc) in crystallographic coordinates
-> and accumulated, to give the supercell
enddo
enddo
enddo


nsb¶

Mnemonics: Number of Supercell points in direction B
Variable type: integer
Dimensions: scalar
Default value: 3

Test list (click to open). Very frequently used, [⅘] in all aim tests, [0/0] in aim tutorials

These variables define a “supercell”, from the primitive cell repeated along each primitive direction. This supercell is build as follows :

  do isa=-nsa,nsa
do isb=-nsb,nsb
do isc=-nsc,nsc
-> here, the cell is translated by the vector
-> (isa,isb,isc) in crystallographic coordinates
-> and accumulated, to give the supercell
enddo
enddo
enddo


nsc¶

Mnemonics: Number of Supercell points in direction C
Variable type: integer
Dimensions: scalar
Default value: 3

Test list (click to open). Very frequently used, [⅘] in all aim tests, [0/0] in aim tutorials

These variables define a “supercell”, from the primitive cell repeated along each primitive direction. This supercell is build as follows :

  do isa=-nsa,nsa
do isb=-nsb,nsb
do isc=-nsc,nsc
-> here, the cell is translated by the vector
-> (isa,isb,isc) in crystallographic coordinates
-> and accumulated, to give the supercell
enddo
enddo
enddo


ntheta¶

Mnemonics: Number of THETA angles
Variable type: integer
Dimensions: scalar
Default value: 32

Test list (click to open). Very frequently used, [5/5] in all aim tests, [0/0] in aim tutorials

With nphi, this variable defines the angular grid for the integration within the Bader volume, in particular, the number of theta angles, to be used between thetamin and thetamax. When the difference between these two variables is $\pi$, the recommended value of ntheta is 32. When it is $\pi$/2 (for symmetry reasons), the recommended value is 20.

phimax¶

Mnemonics: PHI MAXimal angle
Variable type: real
Dimensions: scalar
Default value: 2.0

Test list (click to open). Very frequently used, [⅘] in all aim tests, [0/0] in aim tutorials

Angular limits of integration of the Bader volume for the phi variables. The number of integration points is given by nphi. The range of integration can be decreased if there are symmetry reasons for doing this.

phimin¶

Mnemonics: PHI MINimal angle
Variable type: real
Dimensions: scalar
Default value: 0.0

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

Angular limits of integration of the Bader volume for the phi variables. The number of integration points is given by nphi. The range of integration can be decreased if there are symmetry reasons for doing this.

Variable type: real
Dimensions: scalar
Default value: 0.05

Test list (click to open). Moderately used, [⅖] in all aim tests, [0/0] in aim tutorials

The length of the first step in the search of the exact Bader radius.

ratmin¶

Variable type: real
Dimensions: scalar
Default value: 1.0

Test list (click to open). Moderately used, [⅖] in all aim tests, [0/0] in aim tutorials

The first estimation of the smallest radius of the basin of the atom (the distance at which the procedure that follows the gradient path announces that the gradient path finishes in the corresponding atom) This parameter is very important for the speed of the calculation, but this first estimation is not usually used because the program makes a new one based on the knowledge of CPs. In fact after the CP analysis, the new estimation is done by the product of the ad hoc parameter coff1 (default 0.98) by the distance of the nearest bonding CP. If there is a problem later, coff2 (default 0.95) is used instead.

rsurdir¶

Variable type: real
Dimensions: (2)
Default value: 2*0.0

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

In the case rsurf=1, gives the direction (angular coordinates theta,phi) along which the radius of the Bader surface is to be determined.

rsurf¶

Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

Drive the computation of the radius of the Bader surface for the angles specified in the input variable rsurdir

• 0, not calculated
• 1, calculated

scal¶

Mnemonics: SCALing of the cartesian coordinates
Variable type: real
Dimensions: (3)
Default value: 1.0 1.0 1.0

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

SCALing of the cartesian coordinates.

surf¶

Mnemonics: computation of the bader SURFace
Variable type: integer
Dimensions: scalar
Default value: 0

Test list (click to open). Very frequently used, [5/5] in all aim tests, [0/0] in aim tutorials

Drive the computation of the full Bader surface.

• 0, not calculated
• 1, calculated

thetamax¶

Mnemonics: THETA MAXimal angle
Variable type: real
Dimensions: scalar
Default value: $\pi$

Test list (click to open). Very frequently used, [⅘] in all aim tests, [0/0] in aim tutorials

Angular limits of integration of the Bader volume for the theta variables. The number of integration points is given by ntheta. The range of integration can be decreased if there are symmetry reasons for doing this.

thetamin¶

Mnemonics: THETA MINimal angle
Variable type: real
Dimensions: scalar
Default value: 0.0

Test list (click to open). Rarely used, [0/5] in all aim tests, [0/0] in aim tutorials

Angular limits of integration of the Bader volume for the theta variables. The number of integration points is given by ntheta. The range of integration can be decreased if there are symmetry reasons for doing this.

vpts¶

Mnemonics: Vectors defining the PoinTS of the surface