##master-page:HelpTemplate
##master-date:Unknown-Date
#format wiki
#language en
#Please change following line to BDF module name


= genfrag =


<<TableOfContents(4)>>

{{{
Module genfrag is used to generate molecular fragments and also fragment pairs that are used in Frag-MP2/CCSD calculation.
}}}


== General keywords ==
=== optfrag ===
{{{#!wiki 
 Ask for fragment optimization. Next line is a string "all" or a list of fragments need to be optimized. 
}}}

=== decfrag ===
{{{#!wiki
 Fragments in DEC-(divide-expend-consolidate) MP2/CCSD proposed by Paul Jogensen et. al. are generated.
 If this keyword is not used in input. FragMP2 fragments will be generated.
}}}

=== threshrad ===
{{{#!wiki
 For Frag-MP2, the following line is a float number to specify threshold of buffer radii in FragMP2. Default: 4.5 angstrom.
 For DEC-MP2, the following line is three float numbers to specify thresholds of virtual EOS space, occupied buffer space and unoccupied buffer space.  Default: 4.5 3.0 1.5 angstrom.
 If fragment optimization is required, these threshold are used as initial thresholds.
}}}

=== threshtail ===
{{{#!wiki
 The following line is two float numbers to define threshold of Coulomb tails of occupied and virtual orbitals. Default: 0.01 0.01.
}}}

=== threshexvir ===
{{{#!wiki
 Threshold of extra virtual orbital in Frag-MP2/CCSD approach. Large value will add more extra virtual orbital in amplitude space. Default: 0.1.
}}}

=== distpair ===
{{{#!wiki
 Threshold of distance pairs. Two fragment with distance larger than "dispair" will be neglect in correlation energy calculation. Default: 15 angstrom.
}}}

=== energy ===
{{{#!wiki
  Set the method will be used in correlation calculation. Now, we only support MP2.
}}}

== Expert keywords ==
=== noenergy ===
{{{#!wiki
 Do not evoke energy calculation automatically.
}}}

=== optfrag ===
{{{#!wiki
xxx
}}}

= Depend Files =

|| Filename || Description || Format ||
||          ||             ||        ||

= Examples =

= Insert latex =
You can insert latex formula as 
{{{#!latex
  \begin{equation}
    \rho_{\mu}=\sum_i w_i*\chi_{\mu}(r_i)\chi_{\mu}(r_i)
  \end{equation}
}}}

You can also insert a latex formular inline
    The basis is <<latex($\chi_{\mu}$)>>