# Super-lines¶

ExoCross can use the precomputed _binned_ cross-sections (i.e. with keyword bin) in order to put a line-profile on such a _binned_ transition treating it as a single line with a combined intensity. It is therefore assumed that the corresponding binned-cross-sections are pre-computed for a given T. The advantage of this approach is that calculations of the cross-sections for line-profiles are much faster due to the smaller number of bins relative to the number of lines.

The approximation used is that the line-centres for all transitions within a given bin sifted to the centre of the bin.

This option can be invoked by giving a keyword histogram (or histogram-J, see below) anywhere in the body of the inout file. The states file in this case is used only for the partition function. The histograms (binned-cross-sections) are then given as usual transition files. Otherwise the input file is as usual.

For example:

Temperature  296.0
Range 0.0  10000.0

Npoints 10001

absorption
gauss
hwhm 0.5 (cm-1)

histrogram

output C2H2_ab_g0.5
States       H2O.states
Transitions  H2O_T1000K_bin.xsec


In order to be able using J-dependent Voigt line-profiles, a J-value can be given together with the transition filename. In this case the histrogramJ keyword has to be used instead of histogram.

For example:

histogram-J

Temperature  1000.0
pressure 1
Range 0.0  10000.0

Npoints 1000001

species.
He  gamma 0.0043 n 0.02  t0 298.0 file  1H2-16O__Nina__He__a1.broad model JJ ratio 0.16
H2  gamma 0.0207 n 0.027 t0 298.0 file  1H2-16O__Nina__H2__a1.broad model JJ ratio 0.84
end

absorption
mass 18

output H2O_voi-q_1000K_1bar
offset 25.0

States  1H2-16O__BT2.states

Transitions
bin-J0_T3500_grid1_1e-4.xsec     0
bin-J1_T3500_grid1_1e-4.xsec     1
bin-J2_T3500_grid1_1e-4.xsec     2
bin-J3_T3500_grid1_1e-4.xsec     3
bin-J4_T3500_grid1_1e-4.xsec     4
bin-J5_T3500_grid1_1e-4.xsec     5
end


A histogram can be produced using BIN as the “line-profile” type. This can be combined with the wavelength-range used instead of wavenumber-range (default) by providing um or micron as units in RANGE. Bin’ is used to bin all intensities into different wavenumber/wavelength grid points.

Temperature  296.0
Range 1.0  1000.0  um

Npoints 10001

absorption
bin
`