Absorption cross-sections

Among with RadiativeTransition elements, Radiative processes block now has a CrossSection element, which allows description of absorption cross-section data and vibrational bands assignment in case of complex molecules.

• Description, X and Y elements describe cross-section data in tabular form, where X can be absorbed radiation frequency, wavelength or wavenumber in a form of a list of values or sequence. Y then represents a sequence of sigma values.
• Species element may have StateRef and/or SpeciesRef child elements, indicating species or specific states, to which crossection data applies.
• BandAssignment allows to indicate specific vibrational modes in cross-section data.

Example cross-sections record

Warning: DataList is truncated for clarity, originally it contains 880 space-separated numbers. You may see the original element in schema examples (tests/valid/azulene-working.xml).

<CrossSection>
        <SourceRef>B_NIST1</SourceRef>

        <Description>The IR transmittance cross section of azulene from the NIST
        Standard Reference Data Program Collection</Description>

        <X parameter="wavenumber" units="1/cm">
                <LinearSequence n="880" units="1/cm" a0="450." a1="4"/>
        </X>
        <Y parameter="sigma" units="arbitrary">
                <DataList n="880">
                        0 85 94 .. 102
                </DataList>
        </Y>

        <Species>
                <SpeciesRef>X-CUFNKYGDVFVPHO-UHFFFAOYAT</SpeciesRef>
                <StateRef>SX_Azulene-1</StateRef>
        </Species>

        <BandAssignment name="2v1+v2">
                <BandCentre>
                        <Value units="1/cm">410</Value>
                        <Accuracy>2</Accuracy>
                </BandCentre>
                <BandWidth>
                        <Value units="1/cm">40</Value>
                        <Accuracy>5</Accuracy>
                </BandWidth>
                <Modes>
                        <DeltaV modeID="V1">2</DeltaV>
                        <DeltaV modeID="V2">1</DeltaV>
                </Modes>
        </BandAssignment>
        <BandAssignment name="3v4+2v5">
                <BandCentre>
                        <Value units="1/cm">1657</Value>
                        <Accuracy>10</Accuracy>
                </BandCentre>
                <BandWidth>
                        <Value units="1/cm">120</Value>
                        <Accuracy>15.5</Accuracy>
                </BandWidth>
                <Modes>
                        <DeltaV modeID="V2">3</DeltaV>
                        <DeltaV modeID="V3">2</DeltaV>
                </Modes>
        </BandAssignment>

</CrossSection>