input file is:
<input>
<title> LiF, BSE spectrum</title>
<structure speciespath="/opt/exciting/species">
<crystal>
<basevect>3.80402 3.80402 0.00000</basevect>
<basevect>3.80402 0.00000 3.80402</basevect>
<basevect>0.00000 3.80402 3.80402</basevect>
</crystal>
<species speciesfile="Li.xml">
<atom coord="0.0000 0.0000 0.0000" bfcmt="0.0 0.0 0.0" />
</species>
<species speciesfile="F.xml">
<atom coord="0.5000 0.5000 0.5000" bfcmt="0.0 0.0 0.0" />
</species>
</structure>
<groundstate lradstep="2" gmaxvr="14.0" lmaxvr="8" ngridk="4 4 4" vkloff="0.05 0.15 0.25">
<solver evaltol="1e-300" type="Lapack" />
</groundstate>
<!— scissors correction 5.7eV = 0.20947H —>
<xs xstype="BSE"
nosym="true"
ngridq="4 4 4"
ngridk="4 4 4"
vkloff="0.05 0.15 0.25"
nempty="3"
lmaxapwwf="3"
lmaxemat="3"
gqmax="3"
broad="0.0073499"
tevout="true"
scissor="0.20947">
<energywindow intv="0.0 1.0"
points="1200" />
<screening screentype="full"
nempty="115" />
<BSE bsetype="singlet"
nstlbsemat="1 5 1 4"
nstlbse="1 5 1 4"
aresbse="false"/>
<qpointset>
<qpoint>0.0 0.0 0.0</qpoint>
</qpointset>
</xs>
</input>
