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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 18, 2015SOFIA Tele Talk
2
Life cycle of Stars
H2D+
http://herschel.jpl.nasa.gov
3
0 20 40 60 801
10
100
1000
10000
n-H2
E
nhan
cem
ent F
acto
r
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
4
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
sapphire22-pole
cold head 10 K
shield 50 K
6
22-Pole Low Temperature Ion Trap
primary ions detector
rf IIrf I
sapphire22-pole
cold head 10 K
shield 50 KOskar Asvany
7Trapping time / ms
Ions
per
Filli
ng
Example: H2+ + H2 H3
+ + H
k(T)Rate Coefficient
8
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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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
13
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+
14
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
15
Role of Nuclear Spin?
Conservation laws: E, J, P, I, …
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p-H2D+ o-H2D+
p-H2
o-H2
o-H2
p-H2
Para – Ortho Conversion
E/K
no scrambling
0
100
200
300
400
17
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
18
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 18, 2015SOFIA Tele Talk
19
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
20
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+
21
Results
H2D+
Δ = 62 MHz (!)O. Asvany et al., PRL 100, 233004 (2008)
22
Results
H2D+
Δ = 62 MHz (!)O. Asvany et al., PRL 100, 233004 (2008)
SOFIA
GREAT Receiver
23
Protostellar Cloud Core I16293A
101
000
111
110
p‐H2D+
o‐H2D+
86 K
0 K
24
Para-H2D+ found in Space
25
Astrochemical Modelling
T
o/p
Physics
Chemistry
Collaboration: Jorma Harju, Olli Sipilä, Paola Caselli
26
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
27
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 18, 2015SOFIA Tele Talk
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