This controls the output of scalar data calculated during the PoissonBoltzmann run. This keyword can be repeated several times to provide various types of data output from APBS. The syntax is
write {type} {format} {stem}

type
 A string indicating what type of data to output:

charge
 Write out the biomolecular charge distribution in units of e_{c} (electron charge) per Å^{3}. (multigrid only)

pot
 Write out the electrostatic potential in units of k_{b} T e_{c}^{1}. (multigrid and finite element)
atompot
Write out the electrostatic potential at each atom in units of k_{b} T e_{c}^{1}. The format for the output must be specified as flat. The values are listed sequentially from 1 to NATOMS. See below for more information about format types. (multigrid and finite element).


smol
 Write out the solvent accessibility defined by the molecular surface definition (see srfm smol). Values are unitless and range from 0 (inaccessible) to 1 (accessible). (multigrid and finite element)

sspl
 Write out the splinebased solvent accessibility (see srfm spl2). Values are unitless and range from 0 (inaccessible) to 1 (accessible) (multigrid and finite element)

vdw
 Write out the van der Waalsbased solvent accessibility (see srfm smol with srad 0.0). Values are unitless and range from 0 (inaccessible) to 1 (accessible). (multigrid and finite element)

ivdw
 Write out the inflated van der Waalsbased ion accessibility (see srfm smol). Values are unitless and range from 0 (inaccessible) to 1 (accessible). (multigrid and finite element)

lap
 Write out the Laplacian of the potential in units of k_{B} T e_{c}^{1} Å^{2}. (multigrid only)

edens
 Write out the "energy density" in units of k_{B} T e_{c}^{1} Å^{2}. (multigrid only)

ndens
 Write out the total mobile ion number density for all ion species in units of M. (multigrid only) The output is calculated according to the formula (for nonlinear PB calculations)
where M is the number of ionic species, c_i is the bulk concentration of each species, q_i is the charge of each species, \phi is the electrostatic potential, k_B is Boltzmann's constant, and T is the temperature.

qdens
 Write out the total mobile charge density for all ion species in units of e_{c} M. (multigrid only) The output is calculated according to the formula (for nonlinear PB calculations)
where M is the number of ionic species, c_i is the bulk concentration of each species, q_i is the charge of each species, \phi is the electrostatic potential, k_B is Boltzmann's constant, and T is the temperature.

dielx
 Write out the dielectric map shifted by 1/2 grid spacing in the xdirection (see READ diel). The values are unitless. (multigrid only)

diely
 Write out the dielectric map shifted by 1/2 grid spacing in the ydirection (see READ diel). The values are unitless. (multigrid only)

dielz
 Write out the dielectric map shifted by 1/2 grid spacing in the zdirection (see READ diel). The values are unitless. (multigrid only)

kappa
 Write out the ionaccessibility kappa map (see READ kappa). The values are in units of Å^{2} (multigrid only)

format
 A string that specifies the format for writing out the data.
 _{dx}
 Write out data in OpenDX format. This is the preferred format for APBS I/O. (multigrid and finite element).

avs
 Write out data in AVS UCD format. (finite element only)

uhbd
 Write out data in UHBD format. (multigrid only)
gz
 Write out OpenDX data in gzipped (zlib) compatible format. Appends .dx.gz to the filename.
flat
Write out data as a plain text file. (multigrid and finite element).

stem
 A string that specifies the path for the output; files are
written to
stem.XYZ , where XYZ is determined by the file format (and
processor rank for parallel calculations). If the pathname contains
spaces, then it must be surrounded by double quotes; e.g., "/path with
spaces/foo.in ".
