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**PROGRAM:**

**NAME**

oeprop - One-Electron Property Program

**DESCRIPTION**

The program

**oeprop**computes expectation values of one-electron property operators using a

one-particle density matrix computed from an eigenvector in PSIF_CHKPT or read in from an

external file. It is currently capable of performing Mulliken population analysis,

computing electric multipole moments through octopole, electrostatic properties at atomic

centers (electrostatic potential, electric field, electric field gradient, electron and

spin density, dipolar anisotropic contribution to the hyperfine coupling constants),

electron and spin density, electron and spin density gradient, Laplacian of electron and

spin densities, electrostatic potential over an arbitrary two-dimensional (planar)

rectangular grid, and molecular orbitals values over an arbitrary three-dimensional

rectangular grid. Miscellaneous capabilities include computation of the relativistic

first-order one-electron corrections to the energy (mass-velocity and Darwin terms),

construction of natural molecular orbitals from one-particle density read from an external

file (NOs can be written to PSIF_CHKPT) and computation of spatial extents - expectation

values of X^2, Y^2, Z^2, and R^2 operators - of total electron density and of individual

MOs (if

**READ_OPDM**

**=**false) or natural (if

**READ_OPDM**

**=**true) orbitals (

**MPMAX**must be set to

a value greater than 1 for computing these entities). Spatial extents should be used

cautiously, since they depend on the reference point.

**REFERENCES**

Mulliken population analysis

1. Electronic Population Analysis on LCAO-MO Molecular Wave Functions. R. S.

Mulliken, J. Chem. Phys. 23, 1833 (1955), ibid. 23, 1841 (1955), ibid. 36, 3428

(1962).

Recurrence relations for one-electron integrals over Cartesian Gaussian functions.

1. Efficient recursive computation of molecular integrals over Cartesian Gaussian

functions. S. Obara and A. Saika, J. Phys. Chem. 84, 3963 (1986).

Fundamental physical constants and conversion factors.

1. CRC Handbook of chemistry and physics. Edited by D. R. Lide. 73rd edition

(1992-1993).

**FILES** **REQUIRED**

input.dat - Input file

PSIF_CHKPT - Checkpoint file

**FILES** **UPDATED**

output.dat

dipmom.dat - Dipole moments

esp.dat - Electrostatic potential on a 2D grid

edens.dat - Electron density on a 2D grid

edgrad.dat - Electron density gradient on a 2D grid

edlapl.dat - Laplacian of the electron density on a 2D grid

sdens.dat - Spin density on a 2D grid

sdgrad.dat - Spin density gradient on a 2D grid

sdlapl.dat - Laplacian of the spin density on a 2D grid

mo.dat - Molecular orbital/Density values on a 3D grid

mo.pov - MegaPov input file for rendering an image of mo.dat

mo.cube - Molecular orbital(s) on a 3D grid in Gaussian94 Cube format

dens.cube - Electron/spin density(s) on a 3D grid in Gaussian94 Cube format

**INPUT** **FORMAT**

Most of the keywords are not necessary for routine tasks. The following keywords are

valid:

**WFN**

**=**

__boolean__

Type of the wavefunction. This keyword is a "macro" that allows user to set most of

the necessary keywords. The following values are recognized :

**WFN**

**=**SCF - equivalent to

**READ_OPDM**

**=**false;

**WFN**

**=**DETCI - equivalent to

**READ_OPDM**

**=**true,

**OPDM_FILE**

**=**40,

**OPDM_BASIS**

**=**AO,

**OPDM_FORMAT**

**=**TRIANG;

**WFN**

**=**CCSD - equivalent to

**EAD_OPDM**

**=**true,

**OPDM_FILE**

**=**79,

**OPDM_BASIS**

**=**AO,

**OPDM_FORMAT**

**=**TRIANG;

**WFN**

**=**QVCCD - equivalent to

**READ_OPDM**

**=**true,

**OPDM_FILE**

**=**76,

**OPDM_BASIS**

**=**SO,

**OPDM_FORMAT**

**=**TRIANG;

**READ_OPDM**

**=**

__boolean__

This flag specifies if the one-particle density matrix to be read from disk.

Default is false.

**OPDM_FILE**

**=**

__integer__

Specifies one-particle density matrix file number. Default is 40 (master file). To

provide backward compatibility with the earlier PSI property packages (

**proper**,

**ciprop**,

**ccprop**) special format of the density file is assumed when

**OPDM_FILE**

**=**

**40**

(computing properties from CI density -

**ciprop**compatibility mode) and

**OPDM_FILE**

**=**

**79**(computing properties from CC density -

**ccprop**compatibility mode). As of now,

in generic case onepdm must be written in the very beginning of the file. In the

future PSI will have a standard onepdm file.

**OPDM_BASIS**

**=**

__string__

This option may not exist in the future. As of February 1st, 1998, a standard for

the onepdm file format has not been set. This keyword should be set to either "SO"

(read in onepdm matrix in SO basis) or "AO" (in AO basis). Default is "SO".

**OPDM_FORMAT**

**=**

__string__

This option may not exist in the future. This keyword should be set to either

"TRIANG" (read in onepdm matrix in lower triangular form) of "SQUARE" (in square

form). Default is "TRIANG"

**ASYMM_OPDM**

**=**

__boolean__

This flag specifies whether one-particle density matrix has to be symmetrized.

Must be set to true if generic non-symmetric onepdm to be read (for example, from a

coupled-cluster program). This keyword is for code development only. Existing PSI

CC codes now in use produce symmetric onepdm, therefore there is no need to use

this keyword. Default is false.

**ROOT**

**=**

__integer__

This specifies which root to do the excited state analysis for. The appropriate

one particle density matrix will be read from disk. Currently implemented for

DETCI and DETCAS wavefunctions.

**MPMAX**

**=**

__integer__

This integer between 1 and 3 specifies the highest electric multipole moment to be

computed.

**MPMAX**

**=**1 - only electric dipole moment will be computed (default);

**MPMAX**

**=**2 - electric dipole and quadrupole moments will be computed;

**MPMAX**

**=**3 -

electric dipole, quadrupole, and octopole moments will be computed.

**MP_REF**

__integer__

This parameter specifies the reference point for the electric multipole moments

calculation.

**MP_REF**

**=**0 (default) or 1 - the center of mass;

**MP_REF**

**=**2 - the origin of the space coordinate system;

**MP_REF**

**=**3 - the center of electronic charge;

**MP_REF**

**=**4 - the center of nuclear charge;

**MP_REF**

**=**5 - the center of net charge.

**CAUTION**

**:**According to classical electrodynamics, the electric 2^(n+1)-pole moment

is independent of the reference point only if the electric 2^(n)-pole moment is

vanishing. It means that the dipole moment will depend on the reference point if

the total charge of the system is non-zero. By analogy, electric quadrupole moment

will depend on the reference point if the system possesses non-zero electric dipole

moment, etc.

**MP_REF_XYZ**

**=**

__real_vector__

This vector specifies the coordinates of the reference point. If this keyword is

present in the input

**MP_REF**keyword will be disregarded.

**NUC_ESP**

**=**

__boolean__

This flag specifies if electrostatic properties will be computed at the nuclei.

Current list includes electrostatic potential, electric field, electric field

gradient, electron and spin density, and anisotropic constribution to the hyperfine

coupling constants (the latter two require setting

**SPIN_PROP**to true). Default is

true.

**GRID**

**=**

__integer__

Specifies type of property to be evaluated over a grid.

**GRID**

**=**0 (default) - compute nothing;

**GRID**

**=**1 - electrostatic potential on a two-dimensional grid;

**GRID**

**=**2 - electron density (spin density if

**SPIN_PROP**is set to true) on a two-

dimensional grid;

**GRID**

**=**3 - electron density gradient (spin density gradient if

**SPIN_PROP**is set to

true) on a two-dimensional grid;

**GRID**

**=**4 - Laplacian of the electron density (Laplacian of the spin density if

**SPIN_PROP**is set to true) on a two-dimensional grid. According to the convention

used in the field, what actually gets plotted are the Laplacians taken with

negative sign.

**GRID**

**=**5 - values of molecular orbitals on a three-dimensional grid.

**GRID**

**=**6 - values of the electron density (spin density gradient if

**SPIN_PROP**is

set to true) on a three-dimensional grid.

**GRID_FORMAT**

**=**

__string__

Specifies in which format the grid output will be produced. Currently,

**PLOTMTV**

(default for 2-d grids),

**MEGAPOVPLUS**(available for 3-d grids), and

**GAUSSCUBE**(default for 3-d grids) are supported.

**MO_TO_PLOT**

**=**

__vector__

Specifies indices of the molecular orbitals to be computed on the 3-d grid. Indices

can be specified as:

unsigned integer - index in Pitzer ordering (ordered accoring to irreps, not

eigenvalues). Ranges from 1 to the number of MOs.

signed integer - index with respect to Fermi level. +1 means LUMO, +2 means second

lowest virtual orbital, -1 means HOMO, etc.

All indices have to be either unsigned or signed, you can't mix and match, or you

will get unpredictable results. Default is to compute HOMO and LUMO.

**GRID_ORIGIN**

**=**

__real_vector__

Specifies the origin of the grid. A rectangular grid box which envelops the entire

molecule will be computed automatically if

**GRID_ORIGIN**is missing, however, there

is no default for 2-d grids.

**GRID_UNIT_X**

**=**

__real_vector__

This vector specifies the direction of the first (x) side of the grid. It doesn't

have have to be of unit length. There is no default for 2-d grids.

**GRID_UNIT_Y**

**=**

__real_vector__

The same for the second (y) side. It doesn't have to be of unit length or even

orthogonal to

**GRID_UNIT_X**. There is no default for 2-d grids.

**GRID_XY0**

**=**

__real_2d_vector__

Specifies the coordinates of the lower left corner of the grid rectangle in the 2D

coordinate system defined by GRID_ORIGIN, GRID_UNIT_X, and GRID_UNIT_Y. There is

no default.

**GRID_XY1**

**=**

__real_2d_vector__

Specifies the coordinates of the upper right corner of the grid rectangle in the 2D

coordinate system defined by GRID_ORIGIN, GRID_UNIT_X, and GRID_UNIT_Y. There is

no default.

**GRID_XYZ0**

**=**

__real_3d_vector__

Specifies the coordinates of the far lower left corner of the grid box in the 3D

coordinate system defined by GRID_ORIGIN, GRID_UNIT_X, GRID_UNIT_Y, and the cross-

product of the latter two. There is no default.

**GRID_XYZ1**

**=**

__real_3d_vector__

Specifies the coordinates of the near upper right corner of the grid box in the 3D

coordinate system defined by GRID_ORIGIN, GRID_UNIT_X, GRID_UNIT_Y, and the cross-

product of the latter two. There is no default.

**NIX**

**=**

__integer__

The number of grid point along x direction. This parameter has to be greater than

1. Default is 20.

**NIY**

**=**

__integer__

The same as

**NIX**for y direction. Default is 20.

**NIZ**

**=**

__integer__

The same as

**NIX**for z direction. Default is 20.

**GRID_ZMIN**

**=**

__double__

Lower limit on displayed z-values for contour plots of electron density and its

Laplacian. Default is 0.0

**GRID_ZMAX**

**=**

__double__

Upper limit on displayed z-values for contour plots of electron density and its

Laplacian. Default is 3.0

**EDGRAD_LOGSCALE**

**=**

__integer__

Controls logarithmic scaling of the produced electron density gradient plot. Turns

the scaling off if set to zero, otherwise the higher value - the stronger the

gradient field will be scaled. Recommended value (default) is 5.

**SPIN_PROP**

**=**

__boolean__

Flag for computing spin properties (Mulliken population analysis of alpha and beta

densities, spin densities and anisotropic contributions to the hyperfine coupling

constants at atomic centers). Default is false.

**=**

__integer__

This is the most important keyword - it determines amount of information printed.

The following values are currently used :

**=**0 - quiet mode - print out essential results only - "compact" results of

Mulliken population analysis, electric multipole moments, and electrostatic

properties;

**=**1 (default) - all of the above plus list of tasks to be performed and list

of caculation parameters;

**=**2 - all of the above plus Mulliken AO population matrix and electronic and

nuclear components of electric dipole moment;

**=**3 - all of the above plus density matrix in AO basis and dipole moment

integrals in AO (and SO) basis;

**=**4 - all of the above plus basis set information, natural orbitals in terms

of symmetry orbitals, overlap matrix;

**>=**5 - all of the above plus coupling coefficient vectors, an occupation

vector, and a modified Z-vector in MO basis.

**PRINT_NOS**

**=**

__boolean__

If WRTNOS = TRUE and this option is also TRUE, the natural orbitals will be printed

to output before they are written to the checkpoint file.

**WRTNOS**

**=**

__boolean__

If TRUE, the natural orbitals will be written to the checkpoint file.

**GRID** **OUTPUT** **AND** **PLOTTING**

Currently,

**oeprop**produces output of two-dimensional grids ready for plotting with a

program

**PLOTMTV**version 1.3.2. The program is written by Kenny Toh

([email protected]), software developer for the Technology CAD Department, Intel Corp,

Santa Clara. It is a freeware package, and can be downloaded off the Internet.

Three-dimensional grids are output in format suitable for plotting with a program

**MegaPov**

version 0.5. This freeware program is a patched version of POV-Ray. It is developed by a

number of people, and can be downloaded off the Internet (go to

**http://nathan.kopp.com/patched.htm**to find out more info). To render an MO or density

image, edit (if necessary) command file

**mo.pov**created by

**oeprop**, and execute

**megapovplus**

**+Imo.pov**For more options run

**megapovplus**

**-h**

March 30, 2001 oeprop(1)

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