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..Databases of Infrared Molecular Databases of Infrared Molecular  Parameters  for Astronomy Parameters  for Astronomy

0.7 to 1000 μm (14000 to 10 cm0.7 to 1000 μm (14000 to 10 cm-1-1))

Linda R. BrownLinda R. Brown Jet Propulsion LaboratoryJet Propulsion Laboratory

California Institute of TechnologyCalifornia Institute of TechnologyPasadena, CA 91109Pasadena, CA 91109

linda.brown@jpl.nasa.gov

The research at the Jet Propulsion Laboratory (JPL), California Institute of The research at the Jet Propulsion Laboratory (JPL), California Institute of Technology was performed under contracts with the National Aeronautics Technology was performed under contracts with the National Aeronautics

and Space Administration.and Space Administration.

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ASTRONOMICAL REMOTE SENSING

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Basic transition line parameters:● Line position (or center frequency)● Line intensity @ 296 K● Lower state energy (for temperature dependence)● Vibrational - rotational quantum assignment

Line shape parameters (Voigt) ● Pressure-broadened widths & temperature depend. ● Pressure-induced frequency shifts ● Self-broadened widths Line mixing (limited to CO2; no temp. depend) (Other line shapes: none) ● Continua: collision-induced absorption (CIA)

(given as cross section files)

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Current Public Databases (via Web)Current Public Databases (via Web)

Database Websites (http://) Region cm-1

Num of Species

Num of Transitions

HITRAN 2004

cfa - www.harvard.edu (/hitran)

terrestrial molecules

0.0 to 25233

37 1,734,469

GEISA 2003

ara.lmd.polytechnique.frmolecules

planetary terrestrial

0.0 to 35877

42 (98 iso)

1,668,371

JPL 2005

spec.jpl.nasa.gov molecules,radicals,atoms astrophysics terrestrial

0.0 to 100. (1314.)

(340)

2,644,111

CMSD 2005 (Cologne)

www.ph1.uni-koeln.de molecules,radicals,atoms

astrophysics

0. to 300. (1134.)

(300)

2 M?

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Can’t find your molecule?Can’t find your molecule?Try semi-public customized collectionsTry semi-public customized collections

Databases websites Region

cm-1.

Number of species

Number of transitions

PNNL Air pollution

nwir.pnl.gov 600-6000 336 Cross sections only ($200)

VPL Astrobiology

vpl.ipac.caltech.edu /spectra/

0.000001 –22000 ++

62 PNNL, HITRAN, (team only)

CDSD (CO2)

www.iao.ru ftp://ftp.iao.ru/pub/

0 – 7000 1 (CO2) at 296K, 1000K

Predictions based on modeled data

custom SAO, HITEMP, ATMOS …..

Infrared -astronomy NONE 10 to

14000

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File Structure of HITRAN CompilationFile Structure of HITRAN Compilation

(Java HAWKS) Software and Documentation

Line-by-line

Molecule-by-molecule

IRCross-

sections

AerosolRefractive

Indices

HITRAN(line-transition

parameters)

UV

Global Data Files, Tables,

and References

LineCoupling

Supplemental

Supplemental

Cross-sections

Alternate

CO2 data

Level 1

Level 2

Data

Level 3

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A water transition in 2004 HITRAN:A water transition in 2004 HITRAN:1111 139.782604139.782604 3.822E-193.822E-19 1.168E+001.168E+00..06590659.4228.4228 446.6966446.69660.5900.590.001970.001970

0 0 0 0 0 00 0 0 0 0 0 7 1 7 6 0 67 1 7 6 0 6 555555224433333321216868515100222424** 15.0 13.015.0 13.0

ParameterParameter Field sizeField size DefinitionDefinition

Mol I2 Molecule number

Iso I1 Isotope number (1 = most abundant, 2 = 2nd most abundant,..)

νif F12.6 Transition position in vacuum [cm-1]

Sif E10.3 Intensity [cm-1/(molecule∙cm-2) @ 296K]

Aif E10.3 Einstein A-coefficient [s-1]

γair F5.4 Air-broadened half-width (HWHM) [cm-1/atm @ 296K]

γself F5.4 Self-broadened half-width (HWHM) [cm-1/atm @ 296K]

E″ F10.4 Lower-state energy [cm-1]

nair F4.2 Temperature-dependence coefficient of air width

δair F8.6 Air pressure-induced shift [cm-1/atm @ 296K]

v′, v″ 2A15 Upper and Lower “global” quantum numbers

q′, q″ 2A15 Upper and Lower “local” quantum numbers

ierr 6I1 Uncertainty indices for νif , Sif , γair , γself , nair , δair

iref 6I2 Reference pointers for νif , Sif , γair , γself , nair , δ air

* A1 Flag for line-coupling algorithm (line mixing)

g′, g″ 2F7.1 Upper and Lower statistical weights

> 4 good < 3 bad0 = old (1986)

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CDMS main pageCDMS main page

"www.cdms.de"

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Properties of the CDMS CatalogProperties of the CDMS Catalog

(Mostly) rotational transitions of species for astrophysics and astrochemistry

Molecules detected or detectable in inter/circumstellar medium

Emphasis on Submillimeter and TeraHertz regions

Predictions based on modeling experimental frequencies via Hamiltonians

Separate entries for rarer isotopomers or excited vibrational states (1-1)

Recent entries include – light hydrides and deuterated species: HD2

+, NH, ND, CH2D+, NH2D, NHD2, ND3

– molecules in excited vibrational states: HCN, HNC, HC3N, HC5N, CS, SiO – complex species: ethylene glycol

Format identical to that of JPL catalog

Holger Muller: private communication

> 300 entries as of April 2005

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CDMS: SELECTED ENTRIESCDMS: SELECTED ENTRIESout of 300 speciesout of 300 species

Species N"max K"max max (THz) # lines Uncer.a > 1 MHz @

NH 17 16.489 1948 N" = 10, 10.5 THz

NH2 18 9 18.208 18513 N" < 6, Ka < 4

COb 94 10.330 95 J" = 53, 6.11 THz

HCN 89 7.726 90 J" = 46, 4.13 THz

HC3N 206 1.864 207 J" = 188, 1.7 THz

SO2b 99 44 7.662 13518 2.5 Ka + J 110

(e.g. 5525; 7218)

a Expected to be reliable, exept maybe for HC3N and current SO2 entry. b To be updated soon.

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MASTERMASTER: : MMillimeterwave illimeterwave AAcquisitions for cquisitions for SStratospheric/tratospheric/TTropospheric ropospheric EExchange xchange RResearchesearch

Target molecules HOCL HOBr

COF2 H2O2 HO2 H2CO OCS SO2 NO2

HCN

H2O O3 HNO3 O2 N2O

HCl CO CH3Cl

ClO BrO

+ Interfering species

Initial Source of Line ParametersPositions: JPL (almost always)Intensities: JPL or HITRAN or new calculationsline broadening: literature or new measurements or HITRANline shift: literature or new measurements

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Line-by-line parameters should be Line-by-line parameters should be COMPLETECOMPLETE and and ACCURATEACCURATE ( (ENOUGHENOUGH))

ACCURACIES REQUIRED FOR MANY APPLICATIONS

ν Positions & δ pressure-induced shifts: 0.000001 - 1.0 cm-1

S Line intensities: 1 to 10%

E″ Lower states energies: ½%

γ Pressure-broadening widths: 1 to 20 %

η Temperature dependence of widths: 10 to 40%

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METHODS TO OBTAIN METHODS TO OBTAIN SPECTROSCOPIC PARAMETERSSPECTROSCOPIC PARAMETERS

● Calculations based on successful theoretical modeling (good for positions and intensities, but not line shapes)

● Predictions based on limited data and/or poorer theoretical modeling (warning: extrapolations very poor!)

● Empirical data retrieved line-by-line with some known assignments (warning: no weak lines, larger uncertainties!)

● Absorption cross sections from lab spectra, sometimes at different temperatures (for unresolved heavy species and continua)

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Near-IR (0.7 – 2.5 Near-IR (0.7 – 2.5 μμm) Parameters for earthm) Parameters for earth

SPECIES(HITRAN#)

GENERAL COMMENT

STATUS OF

HITRAN 2000/04

CO (5) BEST CASE Complete Better intensities and broadening available

N2O (4) BEST CASE Almost complete ( a few bands missing )

CO2 (2) GOOD Better accuracies needed; line shape??

Almost complete intensities and positions often inaccurate

O2 (7) FAIR Models good; too much scatter in lab measurements; line shape??

Almost complete intensities and pressure broadening uncertain

H2O (1) FAIR Hamiltonian models fail in NIR; empirical linelists available

Incomplete weak lines missing; some better accuracies needed

O3 (3) FAIR Theory may work well enough; some measurements exists

Incomplete atmospheric bands missing at 2.2 μm

CH4 (6) WORST CASE No Models for NIR; very few measurements available

Incomplete Missing bands: Few assignments (no E″)

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Near-IR Methane Near-IR Methane PositionsPositions and and IntensitiesIntensities::Difficult to model because energy levels perturb each other.Difficult to model because energy levels perturb each other.

Triacontad: intractable: Cross sections orempirical linelist with 1% assignments.

Icosad: almost intractable, but one strong band being studied.Tetradecad: region largely unassigned; no public prediction. Empirical linelist has strongest lines.

Octad: poorer prediction overwritten by some empirical results for main isotope.

Pentad fundamentals and overtones modeled in 3 isotopes; Hot bands intensities are estimated.Dyad and CH3D fundamentals good. Hot bands intensities modeled to 8%.

GS predicted using measured frequencies.Intensities are uncertain and not validated!

cm-1

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Far-IR CH4 Intensities for ground state transitions in HITRAN and GEISA low by 16%?

HITRAN intensities for Far IR set by one “indirect method”, (calc.) [Hilico et al., J Mol Spec, 122, 381(1987)] with claim of accuracy of ± 30%.

Cassam-Chenai, [JQSRT, 82,251(2003)] predicts ab initio Q branch based on Stark measurements [Ozier et al. Phys Rev Lett, 27,1329, (1971)].The intensities are 16% higher than HITRAN values.

Lab data (left) confirms a higher value for R branch manifolds.

Lab Spectra of Far-IR CH4 (Wishnow)

hitran fit from Orton

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HITRAN 2004 Far-IR Water Positions (frequencies) well-studied

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H2O Line IntensitiesAll isotopologues important but not validated

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Warnng! Warning!Warnng! Warning!Far-IR Water Intensities are not Far-IR Water Intensities are not measuredmeasured

Isotope Intensity accuracy and source

11 139.782604 3.822E-19 1.168E+00.0659.4228 446.69660.590.001970 0 0 0 0 0 0 7 1 7 6 0 6 55524333216851 224 15.0 13.0

13 139.997467 1.344E-22 6.538E-01.0919.4389 275.13050.690.004310 0 0 0 0 0 0 5 2 4 4 1 3 50524334226851 224 66.0 54.0

15 140.235360 8.173E-27 1.485E-01.0668.3300 801.35910.490.000000 0 0 0 0 0 0 9 4 6 8 4 5 50554032227 5 2 0 114.0 102.0

14 140.252640 1.725E-24 1.225E-01.0648.3080 942.53220.490.000000 0 0 0 0 0 0 9 5 5 8 5 4 405540 02227 5 2 0 114.0 102.0

12 140.709305 1.269E-24 7.733E-01.0643.2600 1990.85690.41-.010400 0 0 0 0 0 0 11 6 5 11 5 6 40324334222951 2 8 69.0 69.0

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Pressure-broadened Widths (HWHM) are independent of vibration in some molecules.

Coefficients for these widths temperature dependence also are independent of vibration.

Pressured-induced frequency shifts depend on vibration (or position): larger magnitude in Near-IR

Pressure Broadening

1-02-03-03-0

1-02-03-03-0

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Variation of widths by vibrational quantaVariation of widths by vibrational quanta

Methods

a. Predict from the Complex Robert-Bonamy equations.

b. Estimate widths vs quanta by applying the expected theoretical vibrational dependence to empirical widths at different wavelengths.

Left: The estimation method is applied to air-broadened widths of H2O.

□ HITRAN 2000 widths ▲Measured widths

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Self-broadened CHSelf-broadened CH44 widths in near-IR bands widths in near-IR bandsWidths vary as a function of quanta and band.

ν1+ν4 at 4220 cm-1: Widths like those of a 3-fold degenerate (F2) fundamental.

These widths are within 4% of ν3 values (at 3020 cm-1) and other bands with a 3-fold vibrational symmetry (F2).

ν3+ν4 at 4310 cm-1: 9-fold degenerate band: variation of widths at each J is much greater.

ν2+ν3 at 4530 cm-1: 6-fold degenerate band: some variation of widths at each J.Predoi-Cross et al. Multispectrum analysis of 12CH4 from 4100 to 4635 cm-1: 1. self-broadening coefficients

(widths and shifts) – in press J. Mol. Spectrosc.

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Line mixing (line coupling) in waterLine mixing (line coupling) in water

Eight laboratory spectra of water at 6 μm fitted together in order to retrieve the line positions, intensities and line shape coefficients.

The maximum pressure of hydrogen is 1.3 bar at 296 K.

Top: observed-calculated residuals with line mixing

Middle: observed-calculated residuals without line mixing

Bottom: H2-Broadened H2O spectra of two pairs of P and R branch transitions at 1539.5 and 1653 cm-1 in the ν2 band

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Line shape study of pure CO (2 – band)Line shape study of pure CO (2 – band) Residuals differences between observed and synthetic spectraResiduals differences between observed and synthetic spectra are offset by -0.1 and -0.2 (Brault et al. 2003). are offset by -0.1 and -0.2 (Brault et al. 2003). sdVoigt: speed-dependent Voigt profile with line mixing.sdVoigt: speed-dependent Voigt profile with line mixing. sVoigt : speed-dependent “ “ without line mixing.sVoigt : speed-dependent “ “ without line mixing.

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Line mixing observed in COLine mixing observed in CO22 in P and R branches in P and R branches

Top: observed-calculated differences between observed and synthetic spectra for 8 lab scans without line mixing

Middle: observed-calculated residuals with line mixing between P and R branch lines

Bottom: Eight lab spectra of self-Broadened CO2 in the near –IR.Resolution: 0.011 cm-1. Signal to noise: 2000:1.Max. pressure: 1.3 bar (at 296K).

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Models for Collision-Induced ContinuaModels for Collision-Induced Continua

http://www.astro.ku.dk/~aborysow/programs/

A. Borysow, L. Frommhold calculate collision-induced spectra at different temperatures and then form model spectra of cross sections.

Very useful models and software available for generating synthetic spectra

H2-H2, H2-He, H2-CH4, H2-Ar, N2-N2,

CH4-CH4, N2-CH4, CH4-Ar, CO2-CO2

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Low temperature spectrum of methaneLow temperature spectrum of methane

absorption coefficient=-ln(transmission)/(density^2 * path)

First observation of R(3)-R(7) lines

measurements at 0.24 and 0.06 cm-1spectral resolution

Centrifugal distortion dipole lines superposed on collision-induced spectrum.

Dashed line: CH4 Collision-Induced Absorption (CIA) from A. Borysow.

Wishnow, Leung, Gush, Rev. Sci. Inst., 70, 23 (1999)

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CONCLUSIONSCONCLUSIONS

No public infrared database tailored for astronomy

Astronomers use their own private (undocumented) collections

Basic molecular parameters (positions, intensities) available for dozens, not hundreds, of species

Near – IR: parameters missing and inaccurate

Far-IR Insufficient attention to line-by-line intensities

Pressure broadening coefficients needed (models and meas.)

CIA models need to be validated.