The Molden Format

Not all of the below sections are required, you could have {[ATOMS],[GTO] and [MO]} or {[GEOCONV] with [GEOMETRIES]}, or {[FREQ],[FR-COORD],[FR-NORM-COORD], here [INT] is optional}

First Line:

[Molden Format]

Coordinates for the Electron Density/Molecular orbitals:

[Atoms] (Angs|AU)
element_name number atomic_number x y z
...

The workings are with Angstroms or Atomic Units, indicated by the Angs or AU keyword.

Specification of the basis-set consisting of contracted Gaussian Type Orbitals.

[GTO]
atom_sequence_number1 0
shell_label number_of_primitives 1.00
exponent_primitive_1 contraction_coefficient_1 (contraction_coefficient_1)
...
empty line
atom_sequence__number2 0
shell_label number_of_primitives 1.00
exponent_primitive_1 contraction_coefficient_1 (contraction_coefficient_1)
...
empty line

recognized shell_labels:

's','p','d','f','sp','g'

For 'sp' shells two contraction coefficients must be given, for both s and p functions. g-functions are only available since molden4.4 The 0 on the shell_number line and the 1.00 on the shell_label line are no longer functional and can be left out.

All workings with the [GTO] keyword are in Atomic Units.

Specification of the basis-set consisting of contracted Slater Type Orbitals.

[STO]
atom kx ky kz kr alfa norm
...

atom:      the number of the atom on which this orbital is centered
kx,ky,kz:  the exponent of the x,y,z of the orbital
kr:        the exponent of r (root of x*x+y*y+z*z) of the orbital
alfa:      the alfa exponent
norm:      normalization factor

All workings with the [STO] keyword are in Angstroms.

Specification of the molecular orbitals.

The molecular orbitals and their occupation number are specified in the [MO] section. From this information a density matrix can be constructed.

[MO]
 Sym= symmetry_label_1
 Ene= mo_energy_1
 Spin= (Alpha|Beta)
 Occup= mo_occupation_number_1
 ao_number_1 mo_coefficient_1
 ...
 ao_number_n mo_coefficient_n
 ....
 Sym= symmetry_label_N
 Ene= mo_energy_N
 Spin= (Alpha|Beta)
 Occup= mo_occupation_number_N
 ao_number_1 mo_coefficient_1
 ...
 ao_number_n mo_coefficient_n

The following order of D, F en G functions is expected:

   5D: D 0, D+1, D-1, D+2, D-2
   6D: xx, yy, zz, xy, xz, yz

   7F: F 0, F+1, F-1, F+2, F-2, F+3, F-3
  10F: xxx, yyy, zzz, xyy, xxy, xxz, xzz, yzz, yyz, xyz

   9G: G 0, G+1, G-1, G+2, G-2, G+3, G-3, G+4, G-4
  15G: xxxx yyyy zzzz xxxy xxxz yyyx yyyz zzzx zzzy,
       xxyy xxzz yyzz xxyz yyxz zzxy

Use the keyword [5D] on a separate line to specify the use of 'spherical' D and F functions (5 D and 7 F functions). The default is to use 'cartesian' D and F functions (6 D and 10 F functions) . The enable the use of mixed spherical and cartesian function, the following keywords where added ([5D10F] ,[7F] (6D en 7F),[5D7F], (same as[5D], for reasons of backwards compatibility). Since molden4.4 G-functions are also supported, default is cartesian G functions. Use [9G] to specify spherical G functions.

The SCF Convergence section

[SCFCONV]
scf-first n1 THROUGH n2
energy_n1
..
energy_n2
scf-last n1 THROUGH n2
energy_n1
..
energy_n2

The scf-last section is optional.

The Geometry Convergence section

[GEOCONV]
energy
geometry1_energy
...
geometryn_energy
max-force
geometry_1_maximum_force
...
geometry_n_maximum_force
rms-force
geometry_1_rms_force
...
geometry_n_rms_force
max-step
geometry_1_maximum_step
...
geometry_n_maximum_step
rms-step
geometry_1_rms_step
...
geometry_n_rms_step

The max-force, rms-force, max-step and rms-step sections are optional.

[GEOMETRIES] (XYZ|ZMAT)

When specified the XYZ format, supply a concatenated series of XYZ geometries:

Number_of_atoms
title or empty line
atom_1_element_string x y z
...
atom_(Number_of_atoms)_element_string x y z

When ZMAT is specified, supply a concatenated series of Z-matrices in gamess-UK format.
Both XYZ and ZMAT should use angstroms as unit.

Specification of frequencies and corresponding normal coordinates.

The atomic coordinates x,y,z and atomic displacements dx,dy,dz are all in Bohr (Atomic Unit of length).

[FREQ]
frequency_1
...
frequency_n

[FR-COORD]
atom_1_element_string x y z
...
atom_n_element_string x y z

[FR-NORM-COORD]
vibration vibration_number_1
atom_1_dx atom_1_dy atom_1_dz
...
atom_n_dx atom_n_dy atom_n_dz
....
vibration vibration_number_N
atom_1_dx atom_1_dy atom_1_dz
...
atom_n_dx atom_n_dy atom_n_dz

[INT]
ir_intensity_1 [raman_intensity_1]
...
ir_intensity_n [raman_intensity_n]