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Eirík´s project(?) CH3I: agust,www,...rempi/ch3i/PPT ak.ppt

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Presentation on theme: "Eirík´s project(?) CH3I: agust,www,...rempi/ch3i/PPT ak.ppt"— Presentation transcript:

1 Eirík´s project(?) CH3I: agust,www,...rempi/ch3i/PPT ak.ppt ( ) agust,heima,...REMPI/CH3I/PXP ak.pxp Content: pages: compound: availability and physical properties Absorption spectra on www Papers………………………………………………………………… Energetics(?)

2 Eiríks project 1) CH3I: Svana´s , :

3 http://en.wikipedia.org/wiki/Methyl_iodide :
liquid Vapor pressure: CRC: 1 mm 10 40 100 400 760 mp S -45.8oC -24.2 -7.0 +25.3 42.4 -64.4 Vapor pressure = 100 Torr for -7 oC See cooling baths:

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11 ATH 1 ATH 2

12 ATH 1 (2007) agust,heima,...REMPI/CH3I/PXP ak.pxp; Lay:0, Gr:0

13 ATH 1 agust,heima,...REMPI/CH3I/PXP ak.pxp; Lay:0, Gr:0

14 ATH 2 agust,heima,...REMPI/CH3I/PXP aka.pxp; Lay:0, Gr:0

15 Absorption references:

16 Absorption references:

17 Absorption references:
See tables 4-7 in The paper

18 Check REMPI work -by Donovan et al. -references in CH3Br REMPI paper etc. With repect to Rydberg state structure.

19 Papers: See also Eirik´s folder
Rydberg states: RESONANCE-ENHANCED MULTIPHOTON IONIZATION PHOTOELECTRON- SPECTROSCOPY ON NANOSECOND AND PICOSECOND TIME SCALES OF RYDBERG STATES OF METHYL-IODIDE Abstract: Rydberg states of methyl iodide have been investigated using resonance enhanced multiphoton ionization in combination with photoelectron spectroscopy with nanosecond and picosecond laser pulses. The study of the ns (6 less-than-or-equal-to n less-than-or-equal-to 10) Rydberg states in two-, three-, and four-photon excitations has resulted in an unambiguous identification of state [1] in the 7s and 8s Rydberg states. As a consequence, it is concluded that the transition to 6s[1] in two- and three-photon excitations is anomalously weak. The application of photoelectron spectroscopy to identify the electronic and vibrational nature of a resonance has led to a major reinterpretation of the excitation spectrum of the 6p Rydberg state in two-photon excitation. In many of the recorded photoelectron spectra anomalous electrons are observed, which derive from a one-photon ionization process. This process is suggested to find its origin in the mixing of 6p and 7s character into higher-lying Rydberg states. The major difference between resonance enhanced multiphoton ionization photoelectron spectroscopy with nanosecond and picosecond lasers is found in a less effective dissociation of the molecule in the picosecond experiments. ...Ry states, state mixing, vibr. Freq. Modes, (2+1)REMPI spectra and assignments of Rydb. states

20 (2+1)REMPI..3p Ry

21 https://notendur. hi. is/agust/rannsoknir/papers/CH3X/CH3I/jpc86-60-82
Shows 1) mass spectra and 2) energetics

22 Bond energies, ..

23 Less useful but new papers:
1) Isotopic effect in the (2+1) REMPI spectra of (13)C-substituted methyl iodide for UV selective dissociation To investigate a possible means of achieving isotopic enrichment of methyl iodide (CH(3)I), we studied the 6s Rydberg states of (13,12)CH(3)I by (2+1) resonance-enhanced multiphoton ionization. For 3; 3(1)(0) band (v3 hot band) excitation ( at a full width at half maximum of 14 cm (1)), we observed a well-resolved isotope shift of +16 cm (1). The band shape, which has a broad shoulder on the red side and an abrupt decrease on the blue side, indicates that this resonance is ideal for enriching the concentration of the desired lighter isotope (the isotopomer). (C) 2011 Elsevier B.V. All rights reserved. 2) Photoelectron imaging of 8p Rydberg states of atomic iodine following methyl iodide A-band decomposition Photoelectron imaging technique has been applied to study (2 + 1) REMPI of atomic iodine through 8p Rydberg states around 253 nm. Full three-dimensional state-specific speed and angular distributions of the photoelectrons were recorded. The branching ratios among the different I(+) levels revealed that the perturbation on ((3)P(2))8p series is particularly large among the ((3)P(2))np series. The violation of core-conserving ionization is attributed to the interactions between the ((3)P(2))8p and ((1)D(2))6p series. The photoelectron angular distributions were found to be well characterized by P(2)(cos theta) and P(4)(cos theta). A relatively high positive beta(2) and a relatively low beta(4) observed in (2 + 1) REMPI process indicated that the ionization process can be approximately considered as single-photon ionization via the weakly aligned ((3)P(2))8P intermediate states. (C) 2009 Elsevier Inc. All rights reserved.

24 https://notendur. hi. is/agust/rannsoknir/papers/CH3X/CH3I/jams2-93-11

25 URLs: Authors; Titles Important papers:
S. Eden,*,1, P. Lima˜o-Vieira ,2, S.V. Hoffmann , N.J. Mason; VUV spectroscopy of CH3Cl and CH3I R. Locht ,*, B. Leyh, H.W. Jochims , H. Baumgärtel; Medium and high resolution vacuum UV photoabsorption spectroscopy of methyl iodide (CH3I) and its deuterated isotopomers CD3I and CH2DI. A Rydberg series analysis M. R. Dobber, W. J. Buma, and C. A. de Lange ; Resonance enhanced multiphoton ionization photoelectron spectroscopy on nanosecond and picosecond time scales of Rydberg states of methyl iodide David W. CHANDLER, John W. THOMAN Jr. , Maurice H.M. JANSSEN, David H. PARKER ; PHOTOFRAGMENT IMAGING: THE 246 nm PHOTODISSOCL4TION OF CHXI Steven P. Sapers and D.J. Donaldson; A REMPI investigation of methyl iodide Rydberg state predissociation D. H. Parker and R. B. Bernsteln; Multlphoton Ionization-Fragmentation Patterns of Alkyl Iodides Juan Chen et al.; VUV photoionization of (CH3I)n (n = 1-4) molecules. Atsushi Wakai et al.; Isotopic effect in the (2+1) REMPI spectra of 13C-substituted methyl iodide for UV selective dissociation Huan Shen et al.; Photoelectron imaging of 8p Rydberg states of atomic iodine following methyl iodide A-band decomposition Debra Jo Scardino et al.; The multiphoton ionization spectrum of methyl iodide revisted: 1.67–2.2 eV excitation Ian J. McNaught; Structural Parameters of Methyl Iodide by Infrared Spectroscopy Zhiyuan Min, T. Ridley, K.P. Lawley *, R.J. Donovan; Two-colour bound-free-bound spectroscopy of the [2E1/2]c6S Rydberg states of CHgI and CD3I .. T. Ridley, K. P. Lawley* and R. J. Donovan; Ionic and Rydberg states of studied by high resolution CF3 I photoelectron (ZEKE-PFI) and resonance-enhanced multiphoton ionisation spectroscopy

26 URLs: Authors; Titles Important papers:
L. Rubio-Lago et al.; The photodissociation of CH3I in the red edge of the A-band: Comparison between slice imaging experiments and multisurface wave packet calculations Young-Jae Jung et al.; Photoelectron imaging spectroscopy for „211… resonance-enhanced multiphoton ionization of atomic iodine produced from A-band photolysis of CH3I W.C. Price; The Far Ultraviolet Absorption Spectra and Ionization Potentials of the Alkyl Halides. Part I S. FELPS, P. KOCHMANN, P. BRINT, AND S. P. MCGLYNN ; Molecular Rydberg Transitions The Lowest-Energy Rydberg Transitions of s-Type in CH3X and CD3X, X = Cl, Br, and I L 2

27 Now we need to look at the energetics, analogous to that for CH2Br2:
(See slides 6 -11)

28 Fig 10:

29 NIST IE: cm-1

30 cm-1

31 CH3:

32 CH3I D: 2.38 eV cm-1 Factors: f1: 8.36E+01 cm-1 / (kJ mol-1) f2: 3.50E+02 cm-1 / (kcal mol-1) f3: cm-1/eV E(6s) = E(4P;5s)+D= IE(CH3I)= 9.54 NIST IE(I)= E(S/O;I)= E(CH3+I*(1/2))= E(CH3+I+ + e)= IE(CH3) = 9.84 E(CH3+ + e + I) EA(I) = E(CH3+ + I-)= E(I+)-E(I*)=

33 cm-1 CH3I+ + e; 76945.26047 CH3I CH3 + I+ + e; 103491.0874
CH3+ + e + I; CH3I+ + e; CH3 + I**(min); CH3 + I*; CH3 + I; CH3I

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