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<li class="toctree-l1"><a class="reference internal" href="Section_intro.html">1. Introduction</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_accelerate.html">5. Accelerating LAMMPS performance</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_example.html">7. Example problems</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_perf.html">8. Performance &amp; scalability</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_modify.html">10. Modifying &amp; extending LAMMPS</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_python.html">11. Python interface to LAMMPS</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_errors.html">12. Errors</a></li>
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<li class="toctree-l1"><a class="reference internal" href="tutorials.html">Tutorials</a></li>
<li class="toctree-l1"><a class="reference internal" href="commands.html">Commands</a></li>
<li class="toctree-l1"><a class="reference internal" href="fixes.html">Fixes</a></li>
<li class="toctree-l1 current"><a class="reference internal" href="computes.html">Computes</a><ul class="current">
<li class="toctree-l2"><a class="reference internal" href="compute_ackland_atom.html">compute ackland/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_angle.html">compute angle command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_angle_local.html">compute angle/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_angmom_chunk.html">compute angmom/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_basal_atom.html">compute basal/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_body_local.html">compute body/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_bond.html">compute bond command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_bond_local.html">compute bond/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_centro_atom.html">compute centro/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_chunk_atom.html">compute chunk/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_cluster_atom.html">compute cluster/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_cna_atom.html">compute cna/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_com.html">compute com command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_com_chunk.html">compute com/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_contact_atom.html">compute contact/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_coord_atom.html">compute coord/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_damage_atom.html">compute damage/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dihedral.html">compute dihedral command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dihedral_local.html">compute dihedral/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dilatation_atom.html">compute dilatation/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dipole_chunk.html">compute dipole/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_displace_atom.html">compute displace/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dpd.html">compute dpd command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dpd_atom.html">compute dpd/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_erotate_asphere.html">compute erotate/asphere command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_erotate_rigid.html">compute erotate/rigid command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_erotate_sphere.html">compute erotate/sphere command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_erotate_sphere_atom.html">compute erotate/sphere/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_event_displace.html">compute event/displace command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_fep.html">compute fep command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_group_group.html">compute group/group command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_gyration.html">compute gyration command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_gyration_chunk.html">compute gyration/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_heat_flux.html">compute heat/flux command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_hexorder_atom.html">compute hexorder/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_improper.html">compute improper command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_improper_local.html">compute improper/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_inertia_chunk.html">compute inertia/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ke.html">compute ke command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ke_atom.html">compute ke/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ke_atom_eff.html">compute ke/atom/eff command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ke_eff.html">compute ke/eff command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ke_rigid.html">compute ke/rigid command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_meso_e_atom.html">compute meso/e/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_meso_rho_atom.html">compute meso/rho/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_meso_t_atom.html">compute meso/t/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_msd.html">compute msd command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_msd_chunk.html">compute msd/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_msd_nongauss.html">compute msd/nongauss command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_omega_chunk.html">compute omega/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_orientorder_atom.html">compute orientorder/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pair.html">compute pair command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pair_local.html">compute pair/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pe.html">compute pe command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pe_atom.html">compute pe/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_plasticity_atom.html">compute plasticity/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pressure.html">compute pressure command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_property_atom.html">compute property/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_property_chunk.html">compute property/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_property_local.html">compute property/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_rdf.html">compute rdf command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_reduce.html">compute reduce command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_reduce.html#compute-reduce-region-command">compute reduce/region command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_rigid_local.html">compute rigid/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_saed.html">compute saed command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_slice.html">compute slice command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_contact_radius.html">compute smd/contact/radius command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_damage.html">compute smd/damage command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_hourglass_error.html">compute smd/hourglass/error command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_internal_energy.html">compute smd/internal/energy command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_plastic_strain.html">compute smd/plastic/strain command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_plastic_strain_rate.html">compute smd/plastic/strain/rate command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_rho.html">compute smd/rho command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_defgrad.html">compute smd/tlsph/defgrad command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_dt.html">compute smd/tlsph/dt command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_num_neighs.html">compute smd/tlsph/num/neighs command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_shape.html">compute smd/tlsph/shape command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_strain.html">compute smd/tlsph/strain command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_strain_rate.html">compute smd/tlsph/strain/rate command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_stress.html">compute smd/tlsph/stress command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_triangle_mesh_vertices.html">compute smd/triangle/mesh/vertices</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_ulsph_num_neighs.html">compute smd/ulsph/num/neighs command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_ulsph_strain.html">compute smd/ulsph/strain command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_ulsph_strain_rate.html">compute smd/ulsph/strain/rate command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_ulsph_stress.html">compute smd/ulsph/stress command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_vol.html">compute smd/vol command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_sna_atom.html">compute sna/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_sna_atom.html#compute-snad-atom-command">compute snad/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_sna_atom.html#compute-snav-atom-command">compute snav/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_stress_atom.html">compute stress/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_tally.html">compute force/tally command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_tally.html#compute-heat-flux-tally-command">compute heat/flux/tally command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_tally.html#compute-pe-tally-command">compute pe/tally command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_tally.html#compute-pe-mol-tally-command">compute pe/mol/tally command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_tally.html#compute-stress-tally-command">compute stress/tally command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp.html">compute temp command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp.html#compute-temp-kk-command">compute temp/kk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_asphere.html">compute temp/asphere command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_body.html">compute temp/body command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_chunk.html">compute temp/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_com.html">compute temp/com command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_cs.html">compute temp/cs command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_deform.html">compute temp/deform command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_deform_eff.html">compute temp/deform/eff command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_drude.html">compute temp/drude command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_eff.html">compute temp/eff command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_partial.html">compute temp/partial command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_profile.html">compute temp/profile command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_ramp.html">compute temp/ramp command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_region.html">compute temp/region command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_region_eff.html">compute temp/region/eff command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_rotate.html">compute temp/rotate command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_sphere.html">compute temp/sphere command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ti.html">compute ti command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_torque_chunk.html">compute torque/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_vacf.html">compute vacf command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_vcm_chunk.html">compute vcm/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_voronoi_atom.html">compute voronoi/atom command</a></li>
<li class="toctree-l2 current"><a class="current reference internal" href="#">compute xrd command</a><ul>
<li class="toctree-l3"><a class="reference internal" href="#syntax">Syntax</a></li>
<li class="toctree-l3"><a class="reference internal" href="#examples">Examples</a></li>
<li class="toctree-l3"><a class="reference internal" href="#description">Description</a></li>
<li class="toctree-l3"><a class="reference internal" href="#restrictions">Restrictions</a></li>
<li class="toctree-l3"><a class="reference internal" href="#related-commands">Related commands</a></li>
<li class="toctree-l3"><a class="reference internal" href="#default">Default</a></li>
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<li class="toctree-l1"><a class="reference internal" href="angles.html">Angle Styles</a></li>
<li class="toctree-l1"><a class="reference internal" href="dihedrals.html">Dihedral Styles</a></li>
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<div class="section" id="compute-xrd-command">
<span id="index-0"></span><h1>compute xrd command</h1>
<div class="section" id="syntax">
<h2>Syntax</h2>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">compute</span> <span class="n">ID</span> <span class="n">group</span><span class="o">-</span><span class="n">ID</span> <span class="n">xrd</span> <span class="k">lambda</span> <span class="n">type1</span> <span class="n">type2</span> <span class="o">...</span> <span class="n">typeN</span> <span class="n">keyword</span> <span class="n">value</span> <span class="o">...</span>
</pre></div>
</div>
<ul>
<li><p class="first">ID, group-ID are documented in <a class="reference internal" href="compute.html"><span class="doc">compute</span></a> command</p>
</li>
<li><p class="first">xrd = style name of this compute command</p>
</li>
<li><p class="first">lambda = wavelength of incident radiation (length units)</p>
</li>
<li><p class="first">type1 type2 ... typeN = chemical symbol of each atom type (see valid options below)</p>
</li>
<li><p class="first">zero or more keyword/value pairs may be appended</p>
</li>
<li><p class="first">keyword = <em>2Theta</em> or <em>c</em> or <em>LP</em> or <em>manual</em> or <em>echo</em></p>
<pre class="literal-block">
<em>2Theta</em> values = Min2Theta Max2Theta
Min2Theta,Max2Theta = minimum and maximum 2 theta range to explore
(radians or degrees)
<em>c</em> values = c1 c2 c3
c1,c2,c3 = parameters to adjust the spacing of the reciprocal
lattice nodes in the h, k, and l directions respectively
<em>LP</em> value = switch to apply Lorentz-polarization factor
0/1 = off/on
<em>manual</em> = flag to use manual spacing of reciprocal lattice points
based on the values of the <em>c</em> parameters
<em>echo</em> = flag to provide extra output for debugging purposes
</pre>
</li>
</ul>
</div>
<div class="section" id="examples">
<h2>Examples</h2>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">compute</span> <span class="mi">1</span> <span class="nb">all</span> <span class="n">xrd</span> <span class="mf">1.541838</span> <span class="n">Al</span> <span class="n">O</span> <span class="mi">2</span><span class="n">Theta</span> <span class="mf">0.087</span> <span class="mf">0.87</span> <span class="n">c</span> <span class="mi">1</span> <span class="mi">1</span> <span class="mi">1</span> <span class="n">LP</span> <span class="mi">1</span> <span class="n">echo</span>
<span class="n">compute</span> <span class="mi">2</span> <span class="nb">all</span> <span class="n">xrd</span> <span class="mf">1.541838</span> <span class="n">Al</span> <span class="n">O</span> <span class="mi">2</span><span class="n">Theta</span> <span class="mi">10</span> <span class="mi">100</span> <span class="n">c</span> <span class="mf">0.05</span> <span class="mf">0.05</span> <span class="mf">0.05</span> <span class="n">LP</span> <span class="mi">1</span> <span class="n">manual</span>
</pre></div>
</div>
<pre class="literal-block">
fix 1 all ave/histo/weight 1 1 1 0.087 0.87 250 c_1[1] c_1[2] mode vector file Rad2Theta.xrd
fix 2 all ave/histo/weight 1 1 1 10 100 250 c_2[1] c_2[2] mode vector file Deg2Theta.xrd
</pre>
</div>
<div class="section" id="description">
<h2>Description</h2>
<p>Define a computation that calculates x-ray diffraction intensity as described
in <a class="reference internal" href="#xrd-coleman"><span class="std std-ref">(Coleman)</span></a> on a mesh of reciprocal lattice nodes defined
by the entire simulation domain (or manually) using a simulated radiation
of wavelength lambda.</p>
<p>The x-ray diffraction intensity, I, at each reciprocal lattice point, k,
is computed from the structure factor, F, using the equations:</p>
<img alt="_images/compute_xrd1.jpg" class="align-center" src="_images/compute_xrd1.jpg" />
<img alt="_images/compute_xrd2.jpg" class="align-center" src="_images/compute_xrd2.jpg" />
<img alt="_images/compute_xrd3.jpg" class="align-center" src="_images/compute_xrd3.jpg" />
<img alt="_images/compute_xrd4.jpg" class="align-center" src="_images/compute_xrd4.jpg" />
<p>Here, K is the location of the reciprocal lattice node, rj is the
position of each atom, fj are atomic scattering factors, LP is the
Lorentz-polarization factor, and theta is the scattering angle of
diffraction. The Lorentz-polarization factor can be turned off using
the optional <em>LP</em> keyword.</p>
<p>Diffraction intensities are calculated on a three-dimensional mesh of
reciprocal lattice nodes. The mesh spacing is defined either (a)
by the entire simulation domain or (b) manually using selected values as
shown in the 2D diagram below.</p>
<a class=""
data-lightbox="group-default"
href="_images/xrd_mesh.jpg"
title=""
data-title=""
><img src="_images/xrd_mesh.jpg"
class="align-center"
width="25%"
height="auto"
alt=""/>
</a><p>For a mesh defined by the simulation domain, a rectilinear grid is
constructed with spacing <em>c</em>*inv(A) along each reciprocal lattice
axis. Where A are the vectors corresponding to the edges of the
simulation cell. If one or two directions has non-periodic boundary
conditions, then the spacing in these directions is defined from the
average of the (inversed) box lengths with periodic boundary conditions.
Meshes defined by the simulation domain must contain at least one periodic
boundary.</p>
<p>If the <em>manual</em> flag is included, the mesh of reciprocal lattice nodes
will defined using the <em>c</em> values for the spacing along each
reciprocal lattice axis. Note that manual mapping of the reciprocal
space mesh is good for comparing diffraction results from multiple
simulations; however it can reduce the likelihood that Bragg
reflections will be satisfied unless small spacing parameters (&lt; 0.05
Angstrom^(-1)) are implemented. Meshes with manual spacing do not
require a periodic boundary.</p>
<p>The limits of the reciprocal lattice mesh are determined by range of
scattering angles explored. The <em>2Theta</em> parameters allows the user
to reduce the scattering angle range to only the region of interest
which reduces the cost of the computation.</p>
<p>The atomic scattering factors, fj, accounts for the reduction in
diffraction intensity due to Compton scattering. Compute xrd uses
analytical approximations of the atomic scattering factors that vary
for each atom type (type1 type2 ... typeN) and angle of diffraction.
The analytic approximation is computed using the formula
<a class="reference internal" href="#colliex"><span class="std std-ref">(Colliex)</span></a>:</p>
<img alt="_images/compute_xrd5.jpg" class="align-center" src="_images/compute_xrd5.jpg" />
<p>Coefficients parameterized by <a class="reference internal" href="#peng"><span class="std std-ref">(Peng)</span></a> are assigned for each
atom type designating the chemical symbol and charge of each atom
type. Valid chemical symbols for compute xrd are:</p>
<table border="1" class="docutils">
<colgroup>
<col width="19%" />
<col width="19%" />
<col width="19%" />
<col width="23%" />
<col width="19%" />
</colgroup>
<tbody valign="top">
<tr class="row-odd"><td>H</td>
<td>He1-</td>
<td>He</td>
<td>Li</td>
<td>Li1+</td>
</tr>
<tr class="row-even"><td>Be</td>
<td>Be2+</td>
<td>B</td>
<td>C</td>
<td>Cval</td>
</tr>
<tr class="row-odd"><td>N</td>
<td>O</td>
<td>O1-</td>
<td>F</td>
<td>F1-</td>
</tr>
<tr class="row-even"><td>Ne</td>
<td>Na</td>
<td>Na1+</td>
<td>Mg</td>
<td>Mg2+</td>
</tr>
<tr class="row-odd"><td>Al</td>
<td>Al3+</td>
<td>Si</td>
<td>Sival</td>
<td>Si4+</td>
</tr>
<tr class="row-even"><td>P</td>
<td>S</td>
<td>Cl</td>
<td>Cl1-</td>
<td>Ar</td>
</tr>
<tr class="row-odd"><td>K</td>
<td>Ca</td>
<td>Ca2+</td>
<td>Sc</td>
<td>Sc3+</td>
</tr>
<tr class="row-even"><td>Ti</td>
<td>Ti2+</td>
<td>Ti3+</td>
<td>Ti4+</td>
<td>V</td>
</tr>
<tr class="row-odd"><td>V2+</td>
<td>V3+</td>
<td>V5+</td>
<td>Cr</td>
<td>Cr2+</td>
</tr>
<tr class="row-even"><td>Cr3+</td>
<td>Mn</td>
<td>Mn2+</td>
<td>Mn3+</td>
<td>Mn4+</td>
</tr>
<tr class="row-odd"><td>Fe</td>
<td>Fe2+</td>
<td>Fe3+</td>
<td>Co</td>
<td>Co2+</td>
</tr>
<tr class="row-even"><td>Co</td>
<td>Ni</td>
<td>Ni2+</td>
<td>Ni3+</td>
<td>Cu</td>
</tr>
<tr class="row-odd"><td>Cu1+</td>
<td>Cu2+</td>
<td>Zn</td>
<td>Zn2+</td>
<td>Ga</td>
</tr>
<tr class="row-even"><td>Ga3+</td>
<td>Ge</td>
<td>Ge4+</td>
<td>As</td>
<td>Se</td>
</tr>
<tr class="row-odd"><td>Br</td>
<td>Br1-</td>
<td>Kr</td>
<td>Rb</td>
<td>Rb1+</td>
</tr>
<tr class="row-even"><td>Sr</td>
<td>Sr2+</td>
<td>Y</td>
<td>Y3+</td>
<td>Zr</td>
</tr>
<tr class="row-odd"><td>Zr4+</td>
<td>Nb</td>
<td>Nb3+</td>
<td>Nb5+</td>
<td>Mo</td>
</tr>
<tr class="row-even"><td>Mo3+</td>
<td>Mo5+</td>
<td>Mo6+</td>
<td>Tc</td>
<td>Ru</td>
</tr>
<tr class="row-odd"><td>Ru3+</td>
<td>Ru4+</td>
<td>Rh</td>
<td>Rh3+</td>
<td>Rh4+</td>
</tr>
<tr class="row-even"><td>Pd</td>
<td>Pd2+</td>
<td>Pd4+</td>
<td>Ag</td>
<td>Ag1+</td>
</tr>
<tr class="row-odd"><td>Ag2+</td>
<td>Cd</td>
<td>Cd2+</td>
<td>In</td>
<td>In3+</td>
</tr>
<tr class="row-even"><td>Sn</td>
<td>Sn2+</td>
<td>Sn4+</td>
<td>Sb</td>
<td>Sb3+</td>
</tr>
<tr class="row-odd"><td>Sb5+</td>
<td>Te</td>
<td>I</td>
<td>I1-</td>
<td>Xe</td>
</tr>
<tr class="row-even"><td>Cs</td>
<td>Cs1+</td>
<td>Ba</td>
<td>Ba2+</td>
<td>La</td>
</tr>
<tr class="row-odd"><td>La3+</td>
<td>Ce</td>
<td>Ce3+</td>
<td>Ce4+</td>
<td>Pr</td>
</tr>
<tr class="row-even"><td>Pr3+</td>
<td>Pr4+</td>
<td>Nd</td>
<td>Nd3+</td>
<td>Pm</td>
</tr>
<tr class="row-odd"><td>Pm3+</td>
<td>Sm</td>
<td>Sm3+</td>
<td>Eu</td>
<td>Eu2+</td>
</tr>
<tr class="row-even"><td>Eu3+</td>
<td>Gd</td>
<td>Gd3+</td>
<td>Tb</td>
<td>Tb3+</td>
</tr>
<tr class="row-odd"><td>Dy</td>
<td>Dy3+</td>
<td>Ho</td>
<td>Ho3+</td>
<td>Er</td>
</tr>
<tr class="row-even"><td>Er3+</td>
<td>Tm</td>
<td>Tm3+</td>
<td>Yb</td>
<td>Yb2+</td>
</tr>
<tr class="row-odd"><td>Yb3+</td>
<td>Lu</td>
<td>Lu3+</td>
<td>Hf</td>
<td>Hf4+</td>
</tr>
<tr class="row-even"><td>Ta</td>
<td>Ta5+</td>
<td>W</td>
<td>W6+</td>
<td>Re</td>
</tr>
<tr class="row-odd"><td>Os</td>
<td>Os4+</td>
<td>Ir</td>
<td>Ir3+</td>
<td>Ir4+</td>
</tr>
<tr class="row-even"><td>Pt</td>
<td>Pt2+</td>
<td>Pt4+</td>
<td>Au</td>
<td>Au1+</td>
</tr>
<tr class="row-odd"><td>Au3+</td>
<td>Hg</td>
<td>Hg1+</td>
<td>Hg2+</td>
<td>Tl</td>
</tr>
<tr class="row-even"><td>Tl1+</td>
<td>Tl3+</td>
<td>Pb</td>
<td>Pb2+</td>
<td>Pb4+</td>
</tr>
<tr class="row-odd"><td>Bi</td>
<td>Bi3+</td>
<td>Bi5+</td>
<td>Po</td>
<td>At</td>
</tr>
<tr class="row-even"><td>Rn</td>
<td>Fr</td>
<td>Ra</td>
<td>Ra2+</td>
<td>Ac</td>
</tr>
<tr class="row-odd"><td>Ac3+</td>
<td>Th</td>
<td>Th4+</td>
<td>Pa</td>
<td>U</td>
</tr>
<tr class="row-even"><td>U3+</td>
<td>U4+</td>
<td>U6+</td>
<td>Np</td>
<td>Np3+</td>
</tr>
<tr class="row-odd"><td>Np4+</td>
<td>Np6+</td>
<td>Pu</td>
<td>Pu3+</td>
<td>Pu4+</td>
</tr>
<tr class="row-even"><td>Pu6+</td>
<td>Am</td>
<td>Cm</td>
<td>Bk</td>
<td>Cf</td>
</tr>
</tbody>
</table>
<p>If the <em>echo</em> keyword is specified, compute xrd will provide extra
reporting information to the screen.</p>
<p><strong>Output info:</strong></p>
<p>This compute calculates a global array. The number of rows in the
array is the number of reciprocal lattice nodes that are explored
which by the mesh. The global array has 2 columns.</p>
<p>The first column contains the diffraction angle in the units (radians
or degrees) provided with the <em>2Theta</em> values. The second column contains
the computed diffraction intensities as described above.</p>
<p>The array can be accessed by any command that uses global values from
a compute as input. See <a class="reference internal" href="Section_howto.html#howto-15"><span class="std std-ref">this section</span></a>
for an overview of LAMMPS output options.</p>
<p>All array values calculated by this compute are &#8220;intensive&#8221;.</p>
</div>
<div class="section" id="restrictions">
<h2>Restrictions</h2>
<p>This compute is part of the USER-DIFFRACTION package. It is only
enabled if LAMMPS was built with that package. See the <a class="reference internal" href="Section_start.html#start-3"><span class="std std-ref">Making LAMMPS</span></a> section for more info.</p>
<p>The compute_xrd command does not work for triclinic cells.</p>
</div>
<div class="section" id="related-commands">
<h2>Related commands</h2>
<p><a class="reference internal" href="fix_ave_histo.html"><span class="doc">fix ave/histo</span></a>,
<a class="reference internal" href="compute_saed.html"><span class="doc">compute saed</span></a></p>
</div>
<div class="section" id="default">
<h2>Default</h2>
<p>The option defaults are 2Theta = 1 179 (degrees), c = 1 1 1, LP = 1,
no manual flag, no echo flag.</p>
<hr class="docutils" />
<p id="xrd-coleman"><strong>(Coleman)</strong> Coleman, Spearot, Capolungo, MSMSE, 21, 055020
(2013).</p>
<p id="colliex"><strong>(Colliex)</strong> Colliex et al. International Tables for Crystallography
Volume C: Mathematical and Chemical Tables, 249-429 (2004).</p>
<p id="peng"><strong>(Peng)</strong> Peng, Ren, Dudarev, Whelan, Acta Crystallogr. A, 52, 257-76
(1996).</p>
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