Type:         Double
  Default:      0.545
  Definition:   Sets the value of the Ewald coefficient, which controls the width of the Gaussian screening charges during
particle mesh Ewald summation for multipole electrostatics. In the absence of the ewald-alpha keyword,
the default value is 0.545, which is appropriate for most applications.

Type:         Integer
Default:      NONE
Definition:   Specifies the PME grid dimension along the x-axis and takes precedence over the pme-grid keyword.

Type:         Integer
Default:      NONE
Definition:   Specifies the PME grid dimension along the y-axis and takes precedence over the pme-grid keyword.

Type:         Integer
Default:      NONE
Definition:   Specifies the PME grid dimension along the z-axis and takes precedence over the pme-grid keyword.

  Type:         Integer
  Default:      NONE
  Definition:   [3 integers]
Sets the dimensions of the reciprocal space grid used during particle mesh Ewald
summation for electrostatics. The three modifiers give the size along the X-, Y- and Z- axes,
respectively. If either the Y- or Z-axis dimensions are omitted, then they are set equal
to the X-axis dimension. The default in the absence of the pme-grid keyword is to set the
grid size along each axis to the smallest value that can be factored by 2, 3, 4 and/or 5
and is at least as large as 1.2 times the axis length in Angstroms.
The value 1.2 can be changed using the pme-mesh-density property.

  Type:         Integer
  Default:      1.2
  Definition:   The default in the absence of the pme-grid keyword is to set the grid size along each
axis to the smallest factor of 2, 3 and/or 5 that is at least as large as
pme-mesh-density times the axis length in Angstroms.

  Type:         Integer
  Default:      5
  Definition:   Sets the order of the B-spline interpolation used during particle mesh Ewald summation for partial charge
or atomic multipole electrostatics. A default value of 5 is used in the absence of the pme-order keyword.