sofia tele talk june cold chemistry in space and laboratory · 3/6/2015 · 1 cold chemistry in...
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1
Cold Chemistry inSpace and Laboratory
Stephan SchlemmerUniversität zu Köln
H2 Formation, OPR and Chemical Clocks
H3+ / H2D+ Isotopic Fractionation, H3
+/H2D+, OPR
H2D+ + H2 THz Spectroscopy in Lab and Space
June 3, 2015SOFIA Tele Talk
2
Life cycle of Stars
H2D+
http://herschel.jpl.nasa.gov
3
Hydrogen Formation on Grain Surfaces
H + H + g H2 + g
4
tot = el ·vib· rot · nuc
Symmetry considerations and Pauli Principle
evenJ = 0
a-para
oddJ = 1
s+ortho
5
0
2
1
0 K
200 K
p-H2 o-H2
E
Lowest Rotational States of H2
Statistical&
ThermalPopulation
ortho / para ratio 3 : 1
6
0
2
1
0 K
200 K
p-H2 o-H2
E
Lowest Rotational States of H2
E
P(E)
TMC = 10 K
Thermal Population
7
Chemical Clock
Flower et al. A&A,449,621, 2006
o/pH2
8
Cold Chemistry inSpace and Laboratory
Stephan SchlemmerUniversität zu Köln
H2 Formation, OPR and Chemical Clocks
H3+ / H2D+ Isotopic Fractionation, H3
+/H2D+, OPR
H2D+ + H2 THz Spectroscopy in Lab and Space
June 3, 2015SOFIA Tele Talk
9
H3+
H2+
H+
He+
H2
HeC+
H2
CO
C
H2
CH+
CH2+
N+H2, e NH3
CH3+
H2CN+
HCO+
CO
HCN,HNC
H2cosmicrays
HCO+, N2H+, HCS+,H2CN+, H3O+, HCO2
+
COCSH2O
N2
HCNCO2
C2H7O+
CH3OH2+
CH3CO+
CH5+
CH3NH3+
CH3CNH+
C2H5CNH+
CH3HC3N+ CH3C3N
C2H5CN
CH3CN
CH3NH2
CH4
CH2CO
CH3OH
C2H5OHCH3OCH3
e
e
e
e
e
e
e
e
e
O
N
CH3OH
H2O
COH2
NH3
HCN
CH3CN
HC3Nhttp://sift.hyperlink.cz/interste.htm
Initial Reactions in Dense Interstellar Clouds
D. Smith and P. Spanel, Mass Spectrometry Reviews, 14 (1995) 255-278.
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H2 + c.r. H2+ + c.r. + e-
H2+ + H2 H3
+ + H
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Isotopic Fractionation
H3+ + HD H2D+ + H2
E. Hugo, O. Asvany and S. Schlemmer, J. Chem. Phys. 130, Art.-No. 164302 (2009)
12
H2D+
D2H+
B. Parise, A. Belloche, F. Du, R. Güsten and K. Menten, A&A 526, A31 (2011)C. Vastel and T.G: Phillips, APJ, 606, L127 (2004)
Cosmic [D]/[H] ~ 1.5·10-5
Deuterated Moleculesin Interstellar Medium
Deuteriumreservoir
[HD]/[H2] ~ 3.0·10-5
Isotope Enrichment[AD]/[AH] ~ 0.1
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Primary Deuteration Reactions
H3+ + HD H2D+ + H2 + 232 K
Reactants
Products
E
CH3+ + HD CH2D+ + H2 + 375 K
C2H2+ + HD C2HD+ + H2 + 550 K
E
AH AD
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H3+
HDH2D+
H2
[H2D+]/[H3+] = S(T) [HD]/[H2]
Equilibrium
Isotopic FractionationIdeal Case – Laboratory Situation
S(T) = kf/kb
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0 20 40 60 801
10
100
1000
10000
n-H2
En
hanc
emen
t Fac
tor
Temperature / K
p-H2
Isotopic Fractionation
S(T) = kf/kb = exp(231.8 K / T)
H3+
HDH2D+
H2
Lab3*10-4
10 K~ 106
Space[HD]/[H2] 3*10-5
T 10 K [H2D+]/[H3
+] ~ 105
Lab3*10-4
10 K ~ 106
Lab?
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H3+
HDH2D+
e-H, D, HD, H2
H2 M
MD+, MH+
[H2D+]/[H3+] = S(T) [HD]/[H2]
Equilibrium
Isotopic FractionationCloud Model
S(T) = kf/(kb + fe- + kM fM)
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0 20 40 60 801
10
100
1000
10000
n-H2
Enha
ncem
ent F
acto
r
Temperature / K
p-H2
Isotopic Fractionation
S(T) = kf/kb
S(T) = kf/(kb + fe- + kM fM)
H3+
HDH2D+
H2
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Astrophysical Observations
N2H+
C18O
visual extinction or “dust density”(gray scale) toward the western core of the IC 5146
Bergin et al. The Astrophysical Journal, 557:209-229, 2001
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0 20 40 60 801
10
100
1000
10000
n-H2
En
hanc
emen
t Fac
tor
Temperature / K
p-H2
Isotopic Fractionation
S(T) = kf/kb = exp(231.8 K / T)
H3+
HDH2D+
H2
Lab3*10-4
10 K~ 106
Space[HD]/[H2] 3*10-5
T 10 K [H2D+]/[H3
+] ~ 105
Lab3*10-4
10 K ~ 106
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H3+ H2D+
H2
HD
Deuteration of H3+
Theory (Thermodynamics)
[HD]/[H2] 3*10-4
T 10 KS(T) 3.6*109
[H2D+]/[H3+] 106
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Experimental Method:
Electrodynamical Trapping
Dieter Gerlich Oskar AsvanySandra Brünken
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22-Pole Low Temperature Ion Trap
primary ions detector
rf IIrf I
sapphire 22-pole
cold head 10 K
shield 50 K
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22-Pole Low Temperature Ion Trap
primary ions detector
rf IIrf I
sapphire 22-pole
cold head 10 K
shield 50 KOskar Asvany
24Trapping time / ms
Ions
per
Filli
ng
Example: H2+ + H2 H3
+ + H
k(T)Rate Coefficient
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RF Ion TrapsMechanical Model
Quadrupole 22-Pole
FAQ: Why 22 poles?
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H3+
H2D+
H5+
H4D+
H3+ + HD H2D+ + H2
[n-H2] = 1.4x1014 cm-3, [HD]/[H2] = 3*10-4, T = 10 K
0.002
Gerlich, Herbst and Roueff, Planetary and Space Science 50, 1291 (2002)
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Current Experiments with para-H2 (J=0,2,…)
1
3
2
4
3
5
O
2
2
4
O
2
4 B
n-H2
p-H2
Raman Spectra
540 nm 560 nm
540 nm 560 nm
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H3+
H2D+
H5+
H4D+
H3+ + HD H2D+ + H2
[p-H2] = 1x1014 cm-3, [HD]/[H2] = 3*10-4, T = 10 K
0.15
Gerlich, Herbst and Roueff, Planetary and Space Science 50, 1291 (2002)
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Log
([H2D
+ ]/[H
3+ ])
Temperature / K
Experimental Results & Modelling
0 10 20 30 40 50
0.1
0.01
3
J=1/J=0 H2
Hugo et al., J.Chem.Phys. 2009, 130, 164302
Gerlich et al. 2002
o/p H2
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Isotopic Fractionation
H3+ + HD H2D+ + H2
and the H2 / H2D+ OPR
o/p-H2D+ + o/p-H2 o/p-H2D+ + o/p-H2
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H3+
00
11
22
10
0 K
100 K
X
p-H3+ o-H3
+
Lowest energy levels of H3
+
E
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H3+ + HD H2D+ + H2
00
11
22
10
101
000
111
110
0 K
100 K
X
p-H3+ o-H3
+ p-H2D+ o-H2D+
33
H3+ + HD H2D+ + H2
00
11
22
10
101
110
0 K
100 K
X
p-H3+ o-H3
+ p-H2D+ o-H2D+
o-H2
000
111
p-H2
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Role of Nuclear Spin?
Conservation laws: E, J, P, I, …
35
p-H2D+ o-H2D+
p-H2
o-H2
o-H2
p-H2
Para – Ortho Conversion
E/K
scrambling
0
100
200
300
400
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p-H2D+ o-H2D+
p-H2
o-H2
o-H2
p-H2
Para – Ortho Conversion
E/K
scrambling
X single Quantum StateGoverns
Deuterium Chemistry? 0
100
200
300
400
37
Laboratory Approach
H2D+ State Distributions
TranslationRotation
Nuclear Spin
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H3+ + HD H2D+ + H2
00
11
10
101
000
111
110
0 K
100 K
X
p-H3+ o-H3
+ p-H2D+ o-H2D+
h
Reaction
39
Light Induced ReactionsSpectroscopy in Traps
primary ionsh
rf IIrf I
sapphire 22-pole
cold head 10 K
shield 50 K
detector
40
relative B coefficients +
conclusions: 1) ab initio predicted (relative) B coefficients reliable2) reaction probability independent of rovib. overtone excitation
signal~B·pop·P·k*
B1 B2
41
Rotational Level Populations of H2D+
pop ~[H3
+]B ·P
TDoppler=(27±2)K
Trot,para=(27±2)K
45%
12% 30%
13%
Tortho/para=(35)K
42
Cold Chemistry inSpace and Laboratory
Stephan SchlemmerUniversität zu Köln
H2 Formation, OPR and Chemical Clocks
H3+ / H2D+ Isotopic Fractionation, H3
+/H2D+, OPR
H2D+ + H2 THz Spectroscopy in Lab and Space
June 3, 2015SOFIA Tele Talk
43
H3+ + HD H2D+ +H2
00
11
10
101
000
111
110
0 K
100 K
X
p‐H3+ o‐H3
+ p‐H2D+ o‐H2D+
H2D+ Detection in Space
372 GHz
44
45
H3+ + HD H2D+ +H2
00
11
10
101
000
111
110
0 K
100 K
X
p‐H3+ o‐H3
+ p‐H2D+ o‐H2D+
Reaction
h
Light Induced Reactions probing H2D+
46
Results
H2D+
Δ = 62 MHz (!)O. Asvany et al., PRL 100, 233004 (2008)
47
Results
H2D+
Δ = 62 MHz (!)O. Asvany et al., PRL 100, 233004 (2008)
SOFIA
GREAT Receiver
48
Protostellar Cloud Core I16293A
101
000
111
110
p‐H2D+
o‐H2D+
86 K
0 K
49
Para-H2D+ found in Space
50
Astrochemical Modelling
T
o/p
Physics
Chemistry
Collaboration: Jorma Harju, Olli Sipilä, Paola Caselli
51
H2D+ observations give an age of at least one million years for a cloud core forming Sun-like stars
S. Brünken et al. Naturedoi:10.1038/nature13924
52
Cold Chemistry inSpace and Laboratory
Stephan SchlemmerUniversität zu Köln
H2 Formation, OPR and Chemical Clocks
H3+ / H2D+ Isotopic Fractionation, H3
+/H2D+, OPR
H2D+ + H2 THz Spectroscopy in Lab and Space
June 3, 2015SOFIA Tele Talk
53
High‐Resolution Spectroscopy of
Interstellar MoleculesCologne Astrophysics Group
Universität zu Köln
Complex Molecules in Laboratory and Space Frank Lewen, Holger Müller, Christian Endres
Carbon Chain MoleculesThomas Giesen
Silcon Carbon MoleculesSven Thorwirth
He‐Clusters Leonid Surin
Trap ExperimentsSandra Brünken, Oskar Asvany, Pavol Jusko
54
THz Action Spectroscopy
Asvany et al. 2008, Phys Rev LettGärtner et al. 2013, J. Phys. Chem. AAsvany et al. 2012, Rev Sci Instr
LIR
H2D+
Frequency Comb
55
Infrared Action Spectroscopy
Asvany et al. 2012, Rev Sci Instr Asvany et al. 2013, Appl Phys B
LIR
CH5+
COLogne TRAP
Accuracy: 0.2 MHz2932.998459(7) cm-1
T = 20.9 +/- 0.4 K
HC
O2+
Prod
ucts
56
Jusko et al. 2014, Phys Rev LettAsvany et al. 2013, Appl Phys BBrünken et al. 2014, ApJL
LIICG
OH-
l-C3H+
2-photon LIR
THz Action Spectroscopy