FITDES

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Extension of MIO-1-1 (and PBC-0-3) for halogens
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The Slater--Koster tables were generated with the slateratom/sktwocent suite.
The basis set is specified in the referenced article (DOI: 10.1021/ct4001922)
Number of integration points (radial, inclination): 300 100
The new scaled-scalar relativistic (ZORA) implementation in slateratom
was used for the calculations of bromine and iodine atoms in the parametrization.

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Parametrization of the repulsive potentials
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Bonds X-C, X-H and X-Y (inter-halogen)
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The fitting was performed on the optimized geometry of a single molecule.
The molecules chosen were CH3X, HX and XY.

The Erepfit program was used, and the repulsive function was first obtained
as a spline of fourth order, with a grid formed by 4 points:
 1. optimal distance - 0.1 bohr
 2. optimal distance + 0.1 bohr
 3. cut-off distance - 0.04 or 0.05 bohr
 4. cut-off distance

The cut-off distance was based on the optimal bonding distance and
a typical 1--3 (second-neighbor) distance.
(For example, a typical 1--3 distance for the Cl--C potential
is the distance between the chlorine and the methyl-carbon in CH3CH2Cl.)
The cut-off distance was obtained as:
  R(cut-off) = R(opt) + 0.7 * ( R(1--3) - R(opt) )

In the fitting, the target atomization energy was adjusted so that
the stretching vibrational frequency matches the reference.
A certain overbinding was introduced in this way, as described in the article.
  
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Bonds X-O and X-N
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The fitting was done with the recently developed automated procedure
introduced in a previous article (DOI: 10.1021/ct200327s).
The list of molecules used for fitting and further details
are presented in the current article.