Input

The (ASCII) input for dos is keyword oriented. Reading input by dos terminates whenever it finds a line END INPUT or the end-of-file, whichever comes first.

Follows a list of keywords with their meaning. Generally keys may occur more than once and the order in which they appear is relevant in some cases. For instance the key energyrange (which defines for what energy values to compute densities-of-states, see below) applies to all items that come after it in input until the next occurrence of energyrange.

Energy scan values

ENERGYRANGE {Npoint=nr} {E-start=e1} {E-end=e2 / E-step=de}

This specifies for which energy values the densities-of-states are computed that are specified after it in the input file and until the next occurrence of ENERGYRANGE.

ENERGYRANGE specifies the lower bound, upper bound and number of equidistant energy values (including end-points). All items are optional with defaults applying for those omitted.

The E end and E-step values determine one another and must therefore not be specified both (or be consistent).

The initial defaults are:

nr=301
e1=-20
de=0.1

All energy data are in eV.

When values have been changed with the key ENERGYVALUE, the so-modified values are the defaults for the next occurrence of ENERGYVALUE.

Peak widening

The peaks in the DOS curves corresponding to the energies of the molecular orbitals are widened by a Lorentzian curve, the width of which can be adjusted.

LORENTZIAN width=width

Initial default width is 0.25 (eV).

As for ENERGYRANGE, the key LORENTZIAN may occur more than once and each occurrence sets the width for all items after it.

Result files

The computed densities-of-states are stored on one or more ascii files, which have to be specified in input.

FILE file

The key FILE may occur any number of times in input. Each time it occurs the specified file is opened by dos. The file must not yet exist and the new file will accumulate (ascii) the densities-of-states data of all DOS items subsequently specified, until the next occurrence of FILE. The first occurrence of the key FILE must be given before any DOS specification (by the keys TDOS, OPDOS, GPDOS, PDOS, see below).

The format of the result file is such that it can be fed directly into gnuplot.

Densities of States

TDOS { title }

TDOS
instructs the program to compute the total density of states.
title (optional)
will appear as title to the section of corresponding Density-of-States data in the result file.

The other types of densities-of-states require block-type keyword input.

OPDOS { title }
Ftype numbers
Ftype numbers
...
SUBEND
Ftype numbers
Ftype numbers
...
END

Ftype
Specifies the type of basis functions to use in the MO expansions. If the primitive basis functions are to be used Ftype must be bas. For the SFO representation Ftype must be one of the irreducible representations of the pointgroup symmetry. All Ftype values in the data block must be consistent: either all are bas or all are irrep labels. The scope of this consistency requirement is the data block of the current key: in a next OPDOS data block, for instance, a different choice may be made.
numbers
Must be a sequence of integers referring to the basis functions to be selected, i.e. the 'μ-set' and 'ν-set' in (3.3.13) etc.
If bas-type basis functions are selected the numbers refer to the overall list of all basis functions as printed in the output file of the adf run. If SFOs are selected the numbers refer to the SFO list of the pertaining symmetry representation without the core functions, see the adf output file.
SUBEND
Must be typed as such and separates the 'μ-set' and the 'ν-set': all records before subend specify together the 'μ-set' and all records below subend comprise the 'ν-set'. Each of these two sections may consist of any number of records.

The input for GPDOS and PDOS are similar, but simpler because only one set of functions ('μ-set') has to be specified, so there is no subend in the data blocks for these keys.

GPDOS { title }
Ftype numbers
Ftype numbers
...
END

PDOS { title }
Ftype numbers
Ftype numbers
...
END

The keys GPDOS, OPDOS, PDOS and (TDOS) may occur any number of times in input and in any order. Each time the DOS key occurs the current energyrange and lorentzian settings apply and the results are written to the current file.

Memory usage

The default value for the maximum amount of memory that can be used by the program to perform the required computations is chosen and defined at the installation of the whole package and is identical to the value for the main programs (adf, band). As for these programs, the actual value can be adjusted for any particular run with certain keywords, in exactly the same way as for adf and band.

Apart from the maximum total amount of memory you can also adjust some related technical parameters. These should only affect efficiency issues and in general you should not adjust them.

For the total amount of memory in Mbytes:

maxmemoryusage n

The default is defined by the installation. The maxmemoryusage value will have been chosen specifically by the user/installer to accomodate his machine(s).

Input control of memory usage is applicable only if dynamical memory allocation has been turned on in the installation (which is the default, but you may have adjusted that).

One of the standard examples of the ADF package contains an application of dos, including a copy of the ascii result file from dos. See also the Examples document.