git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@14950 f3b2605a-c512-4ea7-a41b-209d697bcdaa

doc/html/_sources/compute_ke_eff.txt

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+.. index:: compute ke/eff
+
+compute ke/eff command
+======================
+
+Syntax
+""""""
+
+.. parsed-literal::
+
+   compute ID group-ID ke/eff
+
+* ID, group-ID are documented in :doc:`compute <compute>` command
+* ke/eff = style name of this compute command
+
+Examples
+""""""""
+
+.. parsed-literal::
+
+   compute 1 all ke/eff
+
+Description
+"""""""""""
+
+Define a computation that calculates the kinetic energy of motion of a
+group of eFF particles (nuclei and electrons), as modeled with the
+:doc:`electronic force field <pair_eff>`.
+
+The kinetic energy for each nucleus is computed as 1/2 m v^2 and the
+kinetic energy for each electron is computed as 1/2(me v^2 + 3/4 me
+s^2), where m corresponds to the nuclear mass, me to the electron
+mass, v to the translational velocity of each particle, and s to the
+radial velocity of the electron, respectively.
+
+There is a subtle difference between the quantity calculated by this
+compute and the kinetic energy calculated by the *ke* or *etotal*
+keyword used in thermodynamic output, as specified by the
+:doc:`thermo_style <thermo_style>` command.  For this compute, kinetic
+energy is "translational" and "radial" (only for electrons) kinetic
+energy, calculated by the simple formula above.  For thermodynamic
+output, the *ke* keyword infers kinetic energy from the temperature of
+the system with 1/2 Kb T of energy for each degree of freedom.  For
+the eFF temperature computation via the :doc:`compute temp_eff <compute_temp_eff>` command, these are the same.  But
+different computes that calculate temperature can subtract out
+different non-thermal components of velocity and/or include other
+degrees of freedom.
+
+IMPRORTANT NOTE: The temperature in eFF models should be monitored via
+the :doc:`compute temp/eff <compute_temp_eff>` command, which can be
+printed with thermodynamic output by using the
+:doc:`thermo_modify <thermo_modify>` command, as shown in the following
+example:
+
+.. parsed-literal::
+
+   compute         effTemp all temp/eff
+   thermo_style    custom step etotal pe ke temp press 
+   thermo_modify   temp effTemp
+
+See :doc:`compute temp/eff <compute_temp_eff>`.
+
+**Output info:**
+
+This compute calculates a global scalar (the KE).  This value can be
+used by any command that uses a global scalar value from a compute as
+input.  See :ref:`Section_howto 15 <howto_15>` for an
+overview of LAMMPS output options.
+
+The scalar value calculated by this compute is "extensive".  The
+scalar value will be in energy :doc:`units <units>`.
+
+Restrictions
+""""""""""""
+
+
+This compute is part of the USER-EFF package.  It is only enabled if
+LAMMPS was built with that package.  See the :ref:`Making LAMMPS <start_3>` section for more info.
+
+**Related commands:** none
+
+**Default:** none
+
+
+.. _lws: http://lammps.sandia.gov
+.. _ld: Manual.html
+.. _lc: Section_commands.html#comm