1. CH2Br2: 1) Absorption 2) REMPI scans: overview (slides 12-15) 3) C+ REMPI vs absorption spectrum agust,www,....ch2br2/PPT-010311ak.ppt agust,heima,...CH2Br2/PXP-010311ak.pxp agust,heima,...CH2Br2/PXP-020311ak.pxp agust,heima,...CH2Br2/PXP-050311ak.pxp agust,heima,...CH2Br2/C REMPI-130411jl.pxp

2. Searched for “CH2Br2 absorption” in Google:

7. StructureAuthor(Year)TemperatureWavelength rangeInformation CH2Br2CausleyRussell(1975)298K110-180nm(0.25,0.5,1nm)DetailsDetails | DataData nm

8. Details Structure:CH2Br2 Name:dibromomethane Author(Year):CausleyRussell(1975) Temperature:298K Wavelength range:110-180nm(0.25,0.5,1nm) Bibliography: G.C. Causley and B.R. Russell, "Vacuum ultraviolet absorption spectra of the bromomethanes," J. Chem. Phys. 62, 848-857 (1975). Comments: Extinction coefficients read at 0.25-, 0.5, and 1-nm intervals from Fig. 6 and converted to absorption cross sections (conversion factor 3.8235x10 -21 ). http://www3.hi.is/~agust/rannsoknir/papers/jcp062-848-75.pdf

9. Grein pöntuð (sjá slide 8) 020311:

10. G.C. Causley and B.R. Russell, "Vacuum ultraviolet absorption spectra of the bromomethanes," J. Chem. Phys. 62, 848-857 (1975). Spectrum from paper and digitised spectrum from database superimposed:

11. Ionization limit 83962.3 cm-1 cm-1 Absorption cross section agust,heima,...CH2Br2/PXP-010311ak.pxp; Lay: 0, Gr:0

12. Ionization limit 83962.3 cm-1 Abs. cross section 23.02.11 h 24.02.11 g 25.02.11 f 28.02.11 e 01.03.11 d REMPI scans for C503 agust,heima,...CH2Br2/PXP-020311ak.pxp ; Lay:1, Gr:1; updated 130311 03.03.11 b 02.03.11 c 04.03.11 a See footnotes below: 2hv/cm -1 http://notendur.hi.is/agust/rannsoknir/papers/jpcA114-9991-10.pdf http://notendur.hi.is/agust/rannsoknir/papers/jpcA114-9991-10.pdf Predictions: C atomic lines 05.03.11 i Predictions: http://notendur.hi.is/agust/rannsoknir/rempi/cf3br/Bromine Lines-080910ks.doc Br atomic http://notendur.hi.is/agust/rannsoknir/rempi/cf3br/Bromine Lines-080910ks.doc Lines Broken lines: from 2 P 1/2 solid lines: from 2 P 3/2 07.03.11 j 08.03.11 k 09.03.11 l 10.03.11 m Dye: C503

13. Footnotes: m(100311): ftp://130.208.167.52/Report/REMPI%20REPORT/20110310.htmlftp://130.208.167.52/Report/REMPI%20REPORT/20110310.html l(090311): ftp://130.208.167.52/Report/REMPI%20REPORT/20110309.htmlftp://130.208.167.52/Report/REMPI%20REPORT/20110309.html k(080311): ftp://130.208.167.52/Data/CH2Br2/20110308/readme.txt ; lot fo Br atomic lines ftp://130.208.167.52/Report/REMPI%20REPORT/20110308.html ; Br atomic linesftp://130.208.167.52/Data/CH2Br2/20110308/readme.txtftp://130.208.167.52/Report/REMPI%20REPORT/20110308.html j(070311): ftp://130.208.167.52/Data/CH2Br2/20110307/readme.txt ;Br,H,CH,CH2 spectra in 82120-83028; Br atomic line in 82000-82140ftp://130.208.167.52/Data/CH2Br2/20110307/readme.txt ftp://130.208.167.52/Report/REMPI%20REPORT/20110307.html ; CH in 81760-81900ftp://130.208.167.52/Report/REMPI%20REPORT/20110307.html i(050311): ftp://130.208.167.52/Report/REMPI%20REPORT/20110305.html ; 79500-79360 no good.ftp://130.208.167.52/Report/REMPI%20REPORT/20110305.html a (040311): ftp://130.208.167.52/Data/CH2Br2/20110304/readme.txt & Clear C+ REMPI spectrum ftp://130.208.167.52/Report/REMPI%20REPORT/20110304.html ftp://130.208.167.52/Data/CH2Br2/20110304/readme.txtftp://130.208.167.52/Report/REMPI%20REPORT/20110304.html b(030311): ftp://130.208.167.52/Data/CH2Br2/20110303/readme.txt ; Br atomic lines observed ftp://130.208.167.52/Report/REMPI%20REPORT/20110303.htmlftp://130.208.167.52/Data/CH2Br2/20110303/readme.txtftp://130.208.167.52/Report/REMPI%20REPORT/20110303.html c( 020311): ftp://130.208.167.52/Report/REMPI%20REPORT/20110302.htmlftp://130.208.167.52/Report/REMPI%20REPORT/20110302.html d(010311): ftp://130.208.167.52/Data/CH2Br2/20110301/readme.txt : NO mention about observation of C atomic lines(?) ftp://130.208.167.52/Report/REMPI%20REPORT/20110301.htmlftp://130.208.167.52/Data/CH2Br2/20110301/readme.txtftp://130.208.167.52/Report/REMPI%20REPORT/20110301.html e( 280211): ftp://130.208.167.52/Data/CH2Br2/20110228/readme.txt ; strong Br atomic line seenftp://130.208.167.52/Data/CH2Br2/20110228/readme.txt f(250211): ftp://130.208.167.52/Data/CH2Br2/20110225/readme.txt : C atomic line seen; Br atomic line seen ftp://130.208.167.52/Report/REMPI%20REPORT/20110225.htmlftp://130.208.167.52/Data/CH2Br2/20110225/readme.txtftp://130.208.167.52/Report/REMPI%20REPORT/20110225.html g(240211): ftp://130.208.167.52/Data/CH2Br2/20110224/Readme.txtftp://130.208.167.52/Data/CH2Br2/20110224/Readme.txt ftp://130.208.167.52/Report/REMPI%20REPORT/20110224.html h(230211): ftp://130.208.167.52/Data/CH2Br2/20110223/Readme.txt ftp://130.208.167.52/Report/REMPI%20REPORT/20110223.htmlftp://130.208.167.52/Data/CH2Br2/20110223/Readme.txtftp://130.208.167.52/Report/REMPI%20REPORT/20110223.html Dat for C503:

14. Ionization limit 83962.3 cm-1 Abs. cross section Horisontal lines: REMPI scans (see also slide above) agust,heima,...CH2Br2/PXP-020311ak.pxp ; Lay:1, Gr:1; updated 1970311 See footnotes below: 2hv/cm -1 http://notendur.hi.is/agust/rannsoknir/papers/jpcA114-9991-10.pdf http://notendur.hi.is/agust/rannsoknir/papers/jpcA114-9991-10.pdf Predictions: C atomic lines Predictions: http://notendur.hi.is/agust/rannsoknir/rempi/cf3br/Bromine Lines-080910ks.doc Br atomic http://notendur.hi.is/agust/rannsoknir/rempi/cf3br/Bromine Lines-080910ks.doc Lines Broken lines: from 2 P 1/2 solid lines: from 2 P 3/2 Dye: C503 Dye: R540 14.03.11 a 15.03.11 b 16.03.11 c Weak signals Group of C atomic lines 17.03.11 d Weak signals 18.03.11 e

15. Footnotes: a(140311; dye:R540): ftp://130.208.167.52/Report/REMPI%20REPORT/20110314.html b(15.03.11; dye:R540): ftp://130.208.167.52/Report/REMPI%20REPORT/20110315.html ftp://130.208.167.52/Report/REMPI%20REPORT/20110315.html c(16.03.11; dye:R540): ftp://130.208.167.52/Report/REMPI%20REPORT/20110316.html ftp://130.208.167.52/Report/REMPI%20REPORT/20110316.html d(17.03.11; dye:R540): ftp://130.208.167.52/Report/REMPI%20REPORT/20110317.html e(18.03.11; dye:R540): ftp://130.208.167.52/Report/REMPI%20REPORT/20110318.html

16. Comment (020311): It will be interesting to see if there is a correlation between the CH2+, CH+, C+....spectra and the absorption spectrum shown above. Have a look at this!:

17. Absorption cross section C + REMPI spectra from 040311: c20110_20145 to c20170_20205 Peak at 80663 cm -1 Absorption spectrum G.C. Causley and B.R. Russell, J. Chem. Phys. 62, 848-857 (1975). 7s(b 1 )  =3.01 2hv/cm -1 agust,heima,...CH2Br2/PXP-050311ak.pxp; lay:0; Gr:1 Threshold for C*( 1 D 2 ) + 2hv -> C + + e - 80625.27 cm -1 See: our CH3Br paper Page 9994

18. Comments: The C + REMPI peak fits exactly the absorption peak for CH 2 Br 2 corresponding to transition to the 7s(b 1 ) Rydberg state according to the paper by Causley and Russel (C&R) (http://www3.hi.is/~agust/rannsoknir/papers/jcp062-848-75.pdf)http://www3.hi.is/~agust/rannsoknir/papers/jcp062-848-75.pdf I wonder if the Rydberg state assignment by C&R is correct(?). It is more likely that a (2+n)REMPI spectrum is due to a resonance transition to a p-Rydberg state due selection rules! Are peaks also found at this position (see above) for the CH 2 + and CH + ions? We desperatelly need “Dye power curves” along with the absorption spectrum Most likely C is formed after 2hv excitation to a Rydberg state by channels such as: CH 2 Br 2 ** -> 2HBr + C OR CH 2 Br 2 ** -> H 2 + C + Br 2 NB!: If the former channel is occuring we might see HBr (2+n) REMPI! ERGO: Look for HBr REMPI in the CH 2 Br 2 data. updated 060311

19. agust,heima,...CH2Br2/C REMPI-130411jl.pxp