High-Resolution Spectroscopic Studies of Reaction Intermediates relevant to Atmospheric Chemistry...
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High-Resolution Spectroscopic Studies of Reaction Intermediates relevant to Atmospheric Chemistry Yasuki Endo Department of Basic Science The University
High-Resolution Spectroscopic Studies of Reaction Intermediates
relevant to Atmospheric Chemistry Yasuki Endo Department of Basic
Science The University of Tokyo June/18/2014 ISMS 2014 Urbana
Slide 2
Main Research Interests High-resolution spectroscopy of short
lived reactive species, and complexes FTMW spectroscopy : Observe
pure rotational transitions LIF spectroscopy : Electronic
transitions Short lived species in the gas phase esp. produced in a
supersonic jet Carbon chain molecules Oxygen bearing species
Radical complexes
Slide 3
Vis-UV Laser spectroscopic system YAG Laser pumped dye lasers
with resolution up to 0.02 cm -1
Slide 4
FTMW spectrometer Balle-Flygare type FTMW spectrometer Observe
pure rotational transitions in the 4 40 GHz region
Slide 5
Pulsed Discharge Nozzle Pulse Valve Pulsed electric discharge
1.02.0 kV, 0.2 msec Free radicals Discharge samples containing
appropriate parent molecules in Ar or Ne (0.2 0.5 %) to produce
target species Radical compexes
Slide 6
FTMWmmW Double Resonance Method pump source PDN Sample MW
cavity pulsed MW mm-wave as well as cm-wave sources can be used for
the pump radiation. It is even possible to use optical or IR
sources.
Slide 7
Oxygen Bearing Short lived Species Species with more than one
oxygen atoms HOOH, HOO, FOO, O 3 (well known) X-OO, CH 3 OO, HOOOH,
HOOO, (oxygen chain species cf. carbon chain species) HOCO, H 2 CO
3, HCO 3, CH 2 OO, CH 3 CHOO CH 2 CHO, CH 2 CCHO Oxygen bearing
radical complexes H 2 OOH, ArHO 2, HO 2 H 2 O COHOCO, H 2 OHOCO CH
2 OOH 2 O important in atmospheric chemistry
Slide 8
Studies of the HOCO Radical and the Carbonic Acid Important
players in atmospheric chemistry CO, CO 2 H 2 O, OH, HO 2 Oxidation
reaction of CO OH + CO OHCO (1) HOCO CO 2 + H Hydration of CO 2 CO
2 + H 2 O CO 2 H 2 O (2) H 2 CO 3 (1) M. I. Lester, B. V. Pond, D.
T. Anderson, L. B. Harding, A. F. Wagner, J. Chem. Phys. 113, 9889
(2000). (2) K. I. Peterson, W. Klemperer, J. Chem. Phys. 80, 3439
(1984).
Slide 9
Oxidation reaction of CO Relative energy (kcal/mol) 30 20 10 0
10 t-HOCO (TS4) t-HOCO (TS1) c-HOCO (TS1) OHCO OH+CO H + CO 2 t-TS
C 2v M c-HOCO (TS2) C 2v TS cis-HOCO trans-HOCO OH + CO CO 2 + H
reaction
Slide 10
trans-HOCO and cis-HOCO trans-HOCO Metastable state No gas
phase spectra The most stable state Gas phase spectra known
cis-HOCO 7.6 kcal/mol 1.8 kcal/mol
Slide 11
Spectra of cis- and trans-forms a = 1.3 Debye a = 2.5 Debye
22564.522565.5 22113.5 22114.5 200 Iterations 1 01 0 00 J=1.50.5,
F=21 cis-HOCOtrans-HOCO 1 4.5 Observed for the first time Discharge
a mixture of CO and H 2 O in Ar
Slide 12
Molecular Structures of HOCO cis-HOCO trans-HOCO Data from HOCO
and DOCO Red: assumed
Slide 13
Observation of COtrans-HOCO 6 06 5 05 finally 21 a-type
transitions 2 b-type transitions has been observed
Slide 14
Determined Structure of COHOCO 2.165 176.6 exp. ab inito A
33915.14(2) 33388 B 1273.450(1) 1280 C 1223.250(1) 1233 RCCSD(T) /
aug-cc-pVTZ Carbon side is bonded Fairly short bond length
Slide 15
Possible Existence of the HOCOH 2 O Complex cis-form of HOCO S.
Aloisio, J. S. Francisco, J. Phys. Chem. A104, 404 (2000).
Contribution of the existence of water on the oxidateion of CO
Slide 16
Cyclic Structure of the H 2 OHO 2 Complex O1H3: 1.795 Fairly
short cf. 2.019 (H 2 O) 2 K. Suma, Y. Sumiyoshi, and Y. Endo,
Science 311, 1278 (2006)
Slide 17
Structures of the H 2 OHOCO Complexes and their Relative
Energies
Slide 18
Observed Spectra of H 2 Otrans-HOCO Two series with different
hyperfine patterns
Slide 19
Molecular Constants of H 2 Otrans-HOCO AAab initio a
(B+C)/22450.080(1)2437.687(1)2503 aa 162.9162.9(2) bb 2.43(1)
1.63(5) cc -5.15-5.15(5) aFaF -3.12(6) -3.44(10) T aa 24.66(3)
24.87(14) T aa (H 2 O) 2.53(7) a RCCSD(T) / aug-cc-pVTZ
Slide 20
Determined Molecular Structures 1.823 1.752 (ab initio) Very
short hydrogen bond (c.a. 2.0 ) Binding energy: 8.8 kcal/mol (ab
initio) RCCSD(T) / aug-cc-pVTZ
Slide 21
Observation of the Carbonic Acid H 2 O + CO 2 H 2 OCO 2 complex
studied by FTMW spectroscopy H 2 CO 3 carbonic acid not detected in
the gas phase
Slide 22
Past Theoretical Studies 3 isomers (1)
cis-ciscis-transtrans-trans Stability (2) H 2 CO 3 + n H 2 O CO 2 +
(n + 1) H 2 O half-life, n = 0: 0.18 million years n = 1: 10 hours
n = 2: 2 minutes Endothermic for the production of H 2 CO 3
half-life (log t /s) (1) B. Jnsson et al, Chem. Phys. Lett. 41, 317
(1976). (2) T. Loerting et al., Angew. Chem., Int. Ed. 39, 891
(2000).
Slide 23
Ab initio Calculations 0 00 0 90 180 11 22
cis-ciscis-transtrans-trans MOLPRO 2008.1 CCSD(T)/cc-pVTZ Energy
[kcal/mol] 11 22
Slide 24
Molecular Structure of cis-trans H 2 CO 3 122.9 126.8 1.188
r(C=O) : 1.202 (HCOOH) 1.208 (H 2 CO) r(CO) : 1.343 (HCOOH) 1.425
(CH 3 OH) (O=CO) : 124.9(HCOOH) 1.345 1.357 Although this is a
higher energy isomer, it has a large dipole moment and is rather
easier to detect
Slide 25
Molecular Structure of cis-cis H 2 CO 3 125.7 1.202 r(C=O) :
1.202 (HCOOH) 1.208 (H 2 CO) r(CO) : 1.343 (HCOOH) 1.425 (CH 3 OH)
(O=CO) : 124.9(HCOOH) 1.340 It is the most stable isomer. Spectra
were weaker since the dipole moment is smaller.
Slide 26
Isomers of H 2 CO 3 0 00 0 90 180 11 22
cis-ciscis-transtrans-trans No spectrum was observed for the
trans-trans isomer since the barrier to the cis-trans form is so
low.
Slide 27
Detection of Bicarbonate Radical Slightly exothermic
(RCCSD(T)/cc-pVTZ)
Slide 28
Observed Spectral Pattern Discharge H 2 O + CO 2 mixture, many
paramagnetic lines
Slide 29
An Example of the Observed Line 1000 times accumulation 2 02 1
01 J = 2.5 1.5 F = 3 2 In general, signals were very weak
Slide 30
Determined Molecular Constants for HCO 3 exp.ab initio a FCO 2
b A13725.26(5)1392813752.2 B11263.93(4)1119811310.3 C
6170.11(4)6207 6192.8 aa 130.1(3) -83.4 bb 675.9(3) -794.7 cc
47.57(4) -44.2 aFaF 9.96(5) T aa 5.60(3) T bb 0.68(3) a
RCCSD(T)-F12a / aug-cc-pVTZ b L. Kolesnikova et al., JCP 128,
224302 (2008)
Slide 31
Detection of CH 2 OO Criegee Intermediate (CI): R 1 R 2 COO
(carbonyl oxide) Intermediate in the ozonolysis process of alkene +
O 3 Ozonolysis Process of Alkene: First proposed by Rudolf Criegee
Justus Liebig Ann. Chem. 564, 9 (1949). Angew. Chem., Int. Ed.
Engl. 14, 745 (1975).
Slide 32
Previous studies of CH 2 OO Gas-phase Spectra of CH 2 OO M. I.
Lester group JACS 134, 20045 (2012). Y.P. Lee group Science 340,
174 (2013). No direct information for the structure B-state:
Repulsive
Slide 33
Observed Spectra of CH 2 OO CH 2 OO: 1 01 -0 00 CH 2 OO: 2 02
-1 01 FTMW spectrumFTMW-mmW DR spectrum 400-shots (CH 2 Br 2 + O 2
) disch. now (CH 2 I 2 + O 2 ) disch. : very strong signals
Slide 34
Determined Molecular Structure of CH 2 OO Ab initioFit 1Fit 2 r
OO / 1.3411.344(1)1.345(3) r CO / 1.2681.274(1)1.272(3) r CH (cis)
/ 1.0821.147(15)1.094(1) r CH (trans) / 1.0791.118(7)1.088(4) OOC /
deg. 117.95118.06(2)118.02(3) OCH (cis) / deg.
118.6108.2(22)118.0(6) OCH (trans) / deg. 114.9120.8(13)114.9(fix)
fit / MHz 1.112.83 long O-O bond zwitterion like structure
Structure from CH 2 OO CD 2 OO CH 2 18 O 2 CD 2 18 O 2
Slide 35
More Papers for CH 2 OO FTMW, more isotopologues, refined
structure M. C. McCarthy et al., J. Phys. Chem. Lett., 4, 4133
(2013) Sub-mm wave spectrum A. M. Daly et al., J. Mol. Spectrosc.,
297, 16 (2014)
Slide 36
Detection of Methyl Derivatives Internal Rotation of the
Methyl-tops Higher Barrier due to the interaction with O atom Lower
Barrier 3.7 kcal/mol higher in energy
Slide 37
Rotational Transitions of syn-CH 3 CHOO UV absorption by J. M.
Beames et al. JCP 138, 244307 (2013) red: FTMW blue: FTMW-mmw-DR
(CH 3 CHI 2 + O 2 ) disch.
Slide 38
Observed Transitions of syn-CH 3 CHOO (a) FTMW spectrum (b)
FTMW-mmw-DR spectrum Very small splittings for the internal
rotation
Slide 39
Rotational Transitions of anti-CH 3 CHOO red: FTMW blue:
FTMW-mmw-DR Signals are 1/3 1/4 times weaker than those of syn- CH
3 CHOO
Slide 40
Observed Transitions of anti-CH 3 CHOO Observed by FTMW
spectroscopy Relatively Large AE splittings EA
Slide 41
Determined Parameters for CH 3 CHOO
Slide 42
Water Complex of CH 2 OO 1.872 2.114 Cyclic Structure
(CCSD(T)/aug-cc-pVTZ) Double hydrogen bonds cf. H 2 OHOO Relatively
short OO...HO bond length Enhance hydrogen migration to produce the
OH radical
Slide 43
Rotational Transitions of CH 2 OOH 2 O (CH 2 I 2 + O 2 + H 2 O)
disch. red: FTMW blue: FTMW-mmw-DR Tansitions of CH 2 OOD 2 O were
also observed (detection was confirmed)
Slide 44
Determined Parameters for the Water Complex
Slide 45
Determined Structure 1.910 (1.872 ) 2.123 (2.114 ) The hydrogen
bond is shorter than usual Cyclic structure like HO 2 H 2 O CH 2
OO: proton acceptor
Slide 46
Conclusions for the Studies of Criegees The simplest Criegee,
CH 2 OO, was identified by FTMW spectroscopy, and structure has
been determined. Nakajima and Endo, JCP 139, 101103 (2013) Both
syn- and anti-forms of CH 3 CHOO were identified, where barriers
for the internal rotations were determined. Nakajima and Endo, JCP
140, 101101 (2013) CriegeeWater complex, CH 2 OOH 2 O, was
identified by FTMW spectroscopy, and cyclic form was confirmed,
which is expected to enhance the hydrogen migration producing the
OH radical. Nakajima and Endo, JCP 140, 1034302 (2014)
Slide 47
Other Studies Carbon chain species (FTMW and LIF) CCS, HCCN,
CCCF, CCCCl, SiCCN, SiCCCN, SiCCH Vinoxy derivatives (FTMW and LIF)
CH 2 =CHO, CH 2 =CHS, CHCH 3 =CHO, CH 2 =CCH 3 S, CH 2 =C=CHO
Atomdiatom systems (FTMW) RgOH, RgSH, RgNO, RgCS
Slide 48
Acknowledgement Prof. M. Nakajima (U. Tokyo) Criegees Prof. Y.
Sumiyoshi (Gumma Univ.) Dr. T. Mori (Horiba Co. Ltd.)H 2 CO 3, HCO
3 Dr. T. Oyama (Tokyo Science Univ.)HOCO and other graduate
students Financial Support JSPS funds