1<?xml version="1.0"?>
2<qmcsystem>
3  <particleset name="ion0" size="2">
4    <group name="C">
5      <parameter name="charge">4</parameter>
6      <parameter name="valence">4</parameter>
7      <parameter name="atomicnumber">6</parameter>
8    </group>
9    <attrib name="position" datatype="posArray">
10  0.0000000000e+00  0.0000000000e+00  0.0000000000e+00
11  2.3480414016e+00  0.0000000000e+00  0.0000000000e+00
12</attrib>
13    <attrib name="ionid" datatype="stringArray">
14 C C
15</attrib>
16  </particleset>
17  <particleset name="e" random="yes" randomsrc="ion0">
18    <group name="u" size="4">
19      <parameter name="charge">-1</parameter>
20    </group>
21    <group name="d" size="4">
22      <parameter name="charge">-1</parameter>
23    </group>
24  </particleset>
25</qmcsystem>
26