T5.6-Perrin

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Transcript T5.6-Perrin

Formaldehyde; H

CO: bandes à 3.6 µm

Agnés Perrin L

aboratoire

nteruniversitaire des

ystémes

tmosphériques (

LISA

), CNRS, Université Paris XII, Créteil, France [email protected]

D.Jacquemart, F. Kwabia Tchana, N. Lacome La

boratoire de Dynamique,

nteractions et

éactivité (

LADIR

) , Université Pierre et Marie Curie-Paris 6, France Many thanks to Larry Rothman and to the HITRAN committee 1

H 2 CO: of major tropospheric importance

Source of

H 2 CO

: photo-oxydation of numerous hydrocarbones

Important

for the status of the HO x

H 2 CO plays an important role in the cloud chemistry (liquid phase) In non negligible concentration in the air of polluted industrial cities and during biomass burning

Can be measured in the

IR Astrophysical

UV/VIS

spectral ranges

GOME SCIAMACHY

Formaldehyde in the IR

band 5.7 µm

5.7 µm 3.6 µm & 9 dark bands .

n 4 n 6

Int=1.2

Int=2.8

Intensity in 10 -17 cm -1 /(molecule.cm

-2 )

The

5.7 µm

band of

H

CO

( n 2 band at

1746 cm

-1 ) • • Start to be used for the

simultaneous

detection of

formaldehyde (

2 band@1746cm -1 )

and

formic acid (

3 band @1778 cm -1 )

by pulsed

uantum

ascade

aser spectrometer (Herndon et al)

formic acid:

3 band , see our poster PII-05

Now used by the

MIPAS FTS

spectrometer on the

ENVISAT



first H

satellite

CO profile in the lower stratosphere

Herndon, Zahniser, Nelson Jr., Shorter, McManus, Jiménez, Warneke, & de Gouw, J. Geophys. Res. D112, D10S03, doi:10.1029/2006JD007600, 2007 4

H 2 CO

retrievals by the

ichelson

nterferometer for

assive

tmospheric

ounding (

MIPAS

) instrument

The 5.7 µm band used for H 2 CO retrievals by MIPAS on the

ENVISAT

satellite

Steck, Glatthor, von Clarmann, Fischer, Flaud, Funke, Grabowski, Höpfner, Kellmann, Linden, Perrin, and Stiller

Retrieval of global upper tropospheric and stratospheric formaldehyde (H 2 CO) distributions from high-resolution MIPAS Envisat spectra,

Atmos. Chem. Phys.,

2008 5

Formaldehyde in the IR

3.6 µm

n 1 & n 5 bands + nine dark bands

Int=1.24

Int=2.79

Int in 10 -17 cm -1 /(molecule.cm

-2 )

Region of

3.6µm

(

&

bands)

Strongest IR band which coincides with a window of

transparency

of the atmosphere Used for reliable portable

environmental sensing of H 2 CO on ground-based, aircraft & satellite platforms……

Fourier transform spectroscopy [ Yokelson et al , Rinsland et al ] Tunable Diode Laser Absorption Spectroscopy [ Fried et al.

] Difference-frequency –generation lasers (DFG) Instruments [ Friedfeld, Fraser, Rehle, Curl , Richter, Tittel… ] Cavity leak-out spectroscopy using CO –sideband laser [ Dahnler et al ] .

Presently: used by ACE (FTS instrument) SCISAT onboard of the satellite

(Gaëlle Dufour and Peter Bernarth, Ch.Boone & co workers from the ACE team)

HITRAN: status of formaldehyde in the IR

3.6 µm 5.7 µm

3.6 µm

: the HITRAN linelist ((2700-3000 cm -1 ) for H 2 CO was generated several years ago using, as input,

the historical work of Linda Brown [Brown79].

This HITRAN linelist is

incomplete

incoherent

(errors on the relative intensities) [

Brown79

]. Brown, Hunt & Pine, J. Mol Spectrosc. 75, 406 (1979) 8

Status of the HITRAN linelist at 3.6 µm for H 2 CO Calc

LADIR

LPMA

CH 3 Cl Calc in 2006 Perrin, Valentin, Daumont J. Mol. Struct (2006) 9

The list in HITRAN is

incomplete

incoherent

(errors on the relative intensities) 10

Goal of this work

 Both the

5.7 µm

and

3.6 µm

bands are used for the retrieval of H 2 CO in the atmosphere (

MIPAS

ACE

 The goal is to have accurate and reliable linelists ).

(position, intensity, line shape parameters) in both spectral regions …. But we generated recently two lists at

5.7 µm

and

3.6 µm

….[

Perr3 , Kwab07 , Perrr06 ]

5.7µm: [Perr03] Perrin, Keller, Flaud J Mol Spectrosc 2003;221:192-198, 5.7µm:[Kwab07] Kwabia Tchana , Perrin & Lacome , J Mol Spectrosc 2007;245:141 3.6 µm[Perrr06] Perrin, Valentin and Daumont J of Mol Struct 2006;780-782:28-44.

These two line lists

[Kwabia07, Perrin03

] at

5.7 µm

and [

Perrin06

] at

3.6 µm

respectively…

need to be validated.

Quality of the

line positions:

achieved mainly from analyses of high resolution FTS spectra (LADIR, LPMAA, GSMA)  depends on the complexity of the theoretical model… 5.7µm: [Perr03] Perrin, Keller, Flaud J Mol Spectrosc 2003;221:192-198, 5.7µm:[Kwab07] Kwabia Tchana , Perrin & Lacome , J Mol Spectrosc 2007;245:141 3.6 µm[Perr06] Perrin, Valentin and Daumont J of Mol Struct 2006;780-782:28-44.

Quality of the line positions

The Hamiltonian matrix accounts for A-type Coriolis , B-type Coriolis , C-type Coriolis, Anh armonic type interactions 5.7 µm :

the strong n

band (at 1746 cm -1 ) 

3 dark bands

and n 6 ) ( n 3 , n 4

3.6 µm

: the strong n

 bands

9 dark bands

& n

Excellent line positions at

5.7 µm

Rather good (althouth not perfect) for the 3.6 µm region.

Difficult calculation

5.7µm: [Perr03] Perrin, Keller, Flaud J Mol Spectrosc 2003;221:192-198, 5.7µm:[Kwab07] Kwabia Tchana , Perrin & Lacome , J Mol Spectrosc 2007;245:141 3.6 µm[Perr06] Perrin, Valentin and Daumont J of Mol Struct 2006;780-782:28-44.

Quality of the intensities for the linelists at 5.7 µm & 3.6 µm for H 2 CO: In Refs [ Perr03 , Kwab03 , Perr06 ] the intensity calculations were performed using only

experimental intensity data collected in the literature.

(1) Band intensity measurements (low or medium resolution in

1600-3100cm -1

) both the

5.7 µm

coverning simultaneously

and 3.6 µm

regions Intercomparison ???

(2) Individual line intensities at

3.6 µm

How from line by line intensity mesurements (at 3.6 µm ) can we deduce « band intensities at 3.6 µm » and perform Intercomparaison of the band intensities ( 5.7 µm  3.6 µm )

?????

Uneasy… but possible !!: It is necessary to compute the « total » band intensity. For this goal one must: 1.

Use a good theoretical model which is able to reproduce the individual line intensities in the overall spectral range Compute a « synthetic spectrum » (list of line positions and intensities) Sum the individual line intensities in the spectral range covered by the absorbing band Account correctly from the contributions from the hot bands and for the minor isotopic species 15

1-Existing

band intensities

in the literature Low and medium resolution band intensity measurements for the whole (3.6 to 5.7 µm) spectral range (PNNL) Sharpe, Johnson, Sams, Chu, Rhoderick, Johnson, Appl Spectrosc 58, 1452 (2004) 16

2- Individual line intensities in the literature (at 3.6 µm only)

3.6 µm

: the extensive set of individual line intensities measured by Brown et al. [

Brown79

] HITRAN : the intensities from

Brown-79

were used as a starting point for the generation of the

HITRAN

linelist at

3.6 µm

) .

This set of individual line intensities [ Brown79 ] was also used in the

3.6 µm

linelist of Ref. [ Perr06 ] [Perr06] Perrin, Valentin and Daumont J of Mol Struct 2006;780-782:28-44 .

[

Brown79]

: Brown, Hunt, & Pine J Mol Spect 75 406 (1979), 17

Status of the line intensities at 3.6 µm:

« Calculated band intensities » in

10 -17 .cm

-1 /molecule.cm

-2

at 296K

Calc HITRAN Int=2.01

2700-3000cm -1

PNNL: Int=2.64

2700-3000 cm -1 LPMA

Ratio (

PNNL

HITRAN ) or ( PNNL

Perr06

)

Cl =

1.30

Calc in 2006 Int=2.02

Perr06: Perrin, Valentin, Daumont J. Mol. Struct (2006) PNNL= Sharpe et al. Appl Spectr. 2004;58:1452

Formaldehyde

Calculated band intensities in

10 -17 .cm

-1 /molecule.cm

-2 Calc PNNL: Int=2.85 (2600-3100 cm -1 ) LPMA

Ratio: (

PNNL

Perr06

1.30

CH 3 Cl

Perr06: Int=2.16

Perr06: Perrin, Valentin, Daumont J. Mol. Struct (2006) PNNL= Sharpe et al. Appl Spectr. 2004;58:1452

Intensities at 3.6 µm

• The individual line intensities generated several years ago by Linda Brown & coworkers [ BROW79 ] lead to intensities about 30% weaker than those achieved from recent band intensities measurements 

Sorry Linda !!

 [

BROW-79

: Brown, Hunt, & Pine J Mol Spect 75 406 (1979), 20

Comparison of the existing intensity data in the literature  2.2

 Perr06: (3.6 µm) intensities scaled to Brown 79  Perr03 (5.7 µm) intensities scaled to Nakanaga

Ratio (Int 3.6µm /Int 5.7µm )=1.7 highly improbable

Comparison of the existing intensity data in the literature

Ratio (Int 3.6µm /Int 5.7µm )=1.7 highly improbable Herndon et al 2005: double diode laser measurement @3.6 & 5.7 µm

Purpose of this work

• The measurement of accurate individual line intensities and self- & N 2 -broadened line width (high resolution FTS spectra) • Intensity calculation and update of the databases 23

Experimental details New FTS (Bruker 120HR) spectra were recorded at LADIR in the 1600-3100 cm -1 for pure H H 2 CO 2 CO and for N 2 -broadened Conditions of the FTS recordings (pressure, temperature) were optimized in order to avoid decomposition (and/or) polymerization of H 2 CO.

Pressure in the cell Recording of the spectra 2h Time 8h 24

Experimental details : FTS spectrum recorded at LADIR in the 1600-3100 cm -1 (pure H 2 CO) 25

Line intensity measurements and calculations

• A large set of individual line intensities were measured in both the using the multifit program developed at LPMAA • From these intensities the expansion of the transition moment operators of the expansion of the transitions moments operators for the and n 3 + n n 4 6 , bands n bands at 3 + n 6 , at 5.7 µm n 3.6 µm 1 , ).

n rotation resonances 5 , n 5.7 µm 2 + (resp. n 4 , 2 n and 2 3 n , 4 2 3.6 µm , n + 4 n + 6 n 6 regions n , 2 and 2 n , 6 2 n , + 3 n , 3 n • The calculations account for the various vibration 4 26

Line intensity measurements & calculations 27

Line intensity measurements & calculations

On the average: I New



I Linda * 1.30

Final band intensity calculation This work

3.6 µm 5.7 µm Ratio Ratio (Int 3.6µm /Int 5.7µm )=2.2

Results at 5.7 µm : overview of the n 2 band 30

Airborne measurements of

H 2 CO

and

HCOOH by QCL spectrometer

D112, D10S03, doi:10.1029/2006JD007600, 2007

Results at 3.6 µm : significant improvements even on the relative scale 32

Hans et al. Atm Env. 16,969(1982) Polluted air of Los Angeles LPMA 33

Detailed view of the 3.6 µm band LADIR

(Intensities*1.28) 35

Region of

3.6µm

(

&

bands)

Used for reliable portable

environmental sensing of H 2 CO on ground-based, aircraft & satellite platforms……

Fourier transform spectroscopy [Yokelson et al, Rinsland et al ] Tunable Diode Laser Absorption Spectroscopy [Fried et al.] Difference-frequency –generation lasers (DFG) Instruments [Friedfeld, Fraser, Rehle, Curl , Richter, Tittel…] Cavity leak-out spectroscopy using CO –sideband laser [Dahnler et al ].

!!!  !!!!

All these atmospheric measurements which were retrieved using HITRAN lead to an overestimation of H 2 CO of 28 % 36

H 2 CO: N 2 -broadening studies at

5.7µm

and

3.6 µm

measurements 0.14

0,14 0.12

0,12 0.10

0,10 0.08

0,08 0,06 0.06

J"= 6 0.04

0,04 0,02 (See David Jacquemart) 0.02

0.00

0,00 0 1 2 3 0 5 10 15 20 25 30 J low

No evidence of a vibrational dependence ( 5.7µm

 a " 5 6 7 8

3.6 µm )

Evidence of a J- and K a

0.14

rotational dependence of the linewidths

0.14

10 0.12

0.12

0.10

0.08

0.06

0.04

0.02

0.00

0 0.06

J"= 10 0.04

(see David Jacquemart & Bob Gamache)

0.02

0.00

1 2 3 4

a " 5 6 7 8 9 10 0 1 2 3 4

a " 5 6 7 8 37 9 10

Conclusion

• Using new FTS spectra recorded at high resolution in the 1600-3100 cm -1 spectral range at LADIR a large set of line intensities were measured. • It was possible to determine the absolute intensities both in the 5.7 µm and 3.6 µm regions • The intensities are now coherent in both spectral regions • N 2 - and -self line broadening parameters were measured. Calculations are under process.

The authors gratefully acknowledge a financial support from the French research program "Les Enveloppes Fluides et l'Environnnement, Chimie Atmosphérique" (LEFE-CHAT) from Institut National des Sciences de l'Univers" du CNRS (INSU CNRS).

Fridolin Kwabia Tchana 39

Vibrational bands H H  C  O

Vibration antisym C-H stretching sym C-H stretching

5 B 2

1 A 1



C-O stretching

2 A 1 CH 2 bending

3 A 1 CH 2 bending out of plane bending

6 B 2

4 B 1

4, n4 + n6 , 2 n6 , n3 + n4 , n3 + n6 n1

H 2

CO Type

2843.3 2782.5

1746.0 1500.2 1249.1 1167.3 B A A A B C n 2+ n 4, 2 n 3, n 2+ n 6, n 2+ n 3 2327, 2422, 2494, 2667, 2719,

2782

2843

cm -1 , 2905, 2998, 3000, 3238 40

Problems with the HITRAN linelist at 3.6 µm Missing lines Relative intensities incorrect Absolute scale: HITRAN intensities are too weak by 28% 41

Line position calculations for the 5.7 µm

band (at 1746 cm -1 ) is resonating with the n 3 , n 4

region:

and n 6 (the strong n

weak bands) Infrared data: FTS spectra recorded at LADIR for the n 2 band Hamiltonian matrix for {2 1 , 3 1 ,4 1 ,6 1 } interacting states of H 2 CO 4 1 6 1 3 1 2 1 4 1 W c.c.

c.c.

A-type Coriolis ,

6 1

W c.c.

c.c.

B-type Coriolis

3 1

B C

. W c.c.

1 W Anh

, C-type Coriolis Anh anharmonic type interactions

Excellent line positions at

5.7 µm 5.7µm: [PERR03] Perrin, Keller, Flaud J Mol Spectrosc 2003;221:192-198, 5.7µm:[KWAB07] Kwabia Tchana , Perrin & Lacome , J Mol Spectrosc 2007;245:141

Energy level calculations for the 3.6 µm region Hamiltonian matrix for {2 1 3 1 , 2 1 6 1 ,3 2 , 2 1 4 interacting states of H 1 ,5 2 1 ,1 1 CO ,3 1 6 1 ,3 1 4 1 n

1 6 1 4 2 } and n

(2782 & 2844 cm -1 ) and

9 dark resonating dark bands

v= 2 1 3 1 2 1 6 1 3 2 2 1 4 1 5 1 1 1 3 1 6 1 3 1 4 1 6 2 4 1 6 1 4 2 2 1 3 1 W

C B F

2 1 6 1 3 2 2 1 4 1 5 1 6 2 4 2

C B W

1 1

3 1 6 1 3 1 4 1 4 1 6 1

C F C F A B C W A C F C W B A F A B A F C A W B C F A C B W C F B C C B F F C A F C W A C B A B F A B A C B W B C F C B A F W B B B C A B W A B F A W -type Coriolis B -type C -type F