Dancing a Waltz with Fullerene
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Dancing a waltz with C60 anions
Umesh R. Kadhane
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Acknowledgement
University of Tennessee, USA:Robert N. Compton
Goteborg University, Sweeden:Klavs HansenErika Sunden
Universit de Montral, Canada:James S. Forster
Univ. of New Hampshire, USA:Olaf Echt
Universit Paris-Sud, France:Jaqueline FayetonMichel BaratBruno Lucas
Marie ProtChristophe Jouvet
University of Aarhus, Denmark:Steen Brndsted NielsenPreben HvelplundJens Ulrik Andersen
Kristian StckhelAnne I. S. HolmSubhasis PanjaHenning ZettergrenAnneli Eheldrig
Lund University, Sweeden:Sofia Canton
TIFR, Mumbai:Lokesh C. TribediDeepankar MisraYahspal singh,Aditya Kelkar,K. V. Thulasi Ram,
Ajay Kumar
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Structure of C60
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Few examples of Fullerenes:
http://www.photon.t.u-tokyo.ac.jp/~maruyama/fticr/fullerene.gif(Referred on 23rd Nov 2010)
http://www.photon.t.u-tokyo.ac.jp/~maruyama/fticr/fullerene.gifhttp://www.photon.t.u-tokyo.ac.jp/~maruyama/fticr/fullerene.gifhttp://www.photon.t.u-tokyo.ac.jp/~maruyama/fticr/fullerene.gifhttp://www.photon.t.u-tokyo.ac.jp/~maruyama/fticr/fullerene.gif -
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Collective excitation in C60
Frequency ~ 1015 Hz
Energy ~ 20 eV
Predicted by Bertsch et. al. (1991)
Measured by Hertel et. al. (1992)
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U. Kadhane et al. Phys. Rev. Lett.90, 093401 (2003)U. Kadhane et al. Nucl. Instrum. Methods Phys. Res. B 205, 661 (2003)
0.3
0.4
0.5
0.6
Target atomic number
S16+
I(
)/I()
2.0 2.5 3.0 3.5 4.00
100
200
300
400
500
600
Ly
Ly
Ly
110 MeV S16+
on C60
Counts
Energy (KeV)
Interaction of fast moving heavy ions with C60
S16+ + C60 S15+* + C60+*
S15+* S15+ + hn (X-ray)
110 MeV
10-17 sec
Projectilen=1
n=2n=3
LyLy
Projectilen=1
n=2n=3
LyLy
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4 5 6 7 80.0
0.2
0.40.6
0.8
1.0
1.2
1.4
1.6
1.8
50 MeV Oq+ on C60
Local Plasma Approx. calculationsPlasmon Excitation model
C60
1+
Projectile Charge State
RelativeIoniz
ation
CrossSectionsofC
60
1+
4 5 6 7 80.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
50 MeV Oq+ on C60
Local Plasma Approx. calculationsPlasmon Excitation modelC
60
4+
Projectile Charge State
RelativeIonizationC
rossSectionsofC
60
4+
U. Kadhane et al. Phys. Rev. A (Rap. Comm.) 75, 041201 (2007)U. Kadhane et al. Rad. Phys. Chem. 75, 2046 (2006)
Influence of GDR excitation on C60 ionization
Xq+ + C60 Xq+ + C60*
C60* C60+ + e-
Projectile
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Experimental development:
Design, planning anddrawing of all thevacuum chambers.
Planning, assembly andtesting of Ultra High
Vacuum system (10-8torr in the mainchamber and 10-9 torrin beam line.)
Design, fabrication andtesting of the massspectrometer with thedetectors.
Processing electronics,data acquisition andanalysis.
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Possible application:
Ion thrusters
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0
+
Unit 1 Unit 2 Coupled system
0 0 0
11 1
1 1 1
0 0
System inground state
Photo excitedsystem
Electron capture
Excited state dynamics
U. Kadhane et al. Phys. Rev. E 77, 021901 (2008)
U. Kadhane et al. J. Photochem. Photobio. 197, 110 (2008)
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Ion Storage
Storage rings Ion traps
High energy(MeV and more)
Low energy(Few keVtens keV)
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ELISA :
ELectrostatIc Storagering for ions,Aarhus
C60
-and C
60
2-
protonated Tryptophan
DNA building blocks
Protoporphyrine IX
Various systems investigated
H+
CNNC
X
X
X
X
X = H: TCNQ
X = F: TCNQ-F 4
TCNQ dianions
http://upload.wikimedia.org/wikipedia/en/e/eb/L-tryptophan.pnghttp://upload.wikimedia.org/wikipedia/en/e/eb/L-tryptophan.pnghttp://evolution.berkeley.edu/evosite/history/dna2.shtmlhttp://upload.wikimedia.org/wikipedia/en/e/eb/L-tryptophan.pnghttp://upload.wikimedia.org/wikipedia/commons/4/41/C60a.png -
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Doubly charged negative ions
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0 5 10 15 20
-8
-6
-4
-2
0
2
r ()
Ue
(eV)
C-
60 Free electron
0 5 10 15 20
-8
-6
-4
-2
0
2
r ()
Ue
(eV)
C-
60
R=100Na ion
0 5 10 15 20
-8
-6
-4
-2
0
2
r ()
Ue
(eV)
C-
60
R=50
0 5 10 15 20
-8
-6
-4
-2
0
2
r ()
Ue
(eV)
C-
60
R=20
0 5 10 15 20
-8
-6
-4
-2
0
2
Na+
r ()
Ue
(eV)
C-
60
R=15
0 5 10 15 20
-8
-6
-4
-2
0
2
Na+
r ()
Ue
(eV)
C-
60
R=10
0 5 10 15 20
-8
-6
-4
-2
0
2
Na+
r ()
Ue
(eV)
C-
60
R=Rc=7.6
OVER THE BARRIER ELECTRON TRANSFER
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Bo Liu et. al., Phys. Rev. Lett. 2004
Formation ofC60 dianion invacuum.
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Hckel molecular orbital diagram for C60
Hands et. al. Adv. Quant. Chem.44
, 335 (2003)
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Spectroscopy of C60 dianios
S. Tomota et. al., J. Chem. Phys. 2006
Temperature
control isessential!!!!!
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Nielsen ion source
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Ion source and 14 pole RF trap
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-20V
20V
RF trap schematic
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1 mDetectorfor neutrals
Laser
Ion source
Magnet
Injection
tCounts
ELISA
E* = E0 + hn
Decay of excited molecule
~100 s
Na cell
Channeltron, detector for ions
Mirror
C60-2 C60
- + e-AB+ A+ + B
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Channeltron detector
C60-
C60-2
Detection of charged products after electrondetachment
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0.1 1 10 10010-4
10
-3
10-2
10-1
100
101
C60
2-
Decayrate(a.u
.)
Time (ms)
C702-
200 K
RT
370 K
Temperature measurement on C60 and C70dianions
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0 200 400 600 800 100010-3
10-2
10-1
100
101
355 K
300 K
225 K
C60
2-
C70
2-
Beamc
urrent(a.u
.)
Time (ms)
318 K
Comparison at longer time scale
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0 1 2 3 4 5 6 7 8
2000
4000
6000
8000
10000
12000
14000
3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4
2000
4000
6000
Counts
Time (ms)
930 nm
Spectroscopy of C60 dianions
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Spectroscopy of C602- states
U. Kadhane et al., J. Chem. Phys. 131, 014301(2009)
The similarity betweensolution based
measurements indicatethat the ground state is aSinglet due to strong JTcoupling to quadrupole
deformation.
Hase et. al. Chem. Phys. Lett. 326, 186 (2000)
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Conclusion
Near-infrared absorption spectra of C60 dianions in the gas phaseleads to electron loss by both direct electron tunneling into thecontinuum and statistical autodetachment after internalconversion.
The Coulomb barrier is more than 1.5 eV. Consistent with the
theoretically predicted value of 1.7 eV. The absorption spectra reveal the strong JT interaction inthe dianions of C60, and the electronic ground state is determinedto be singlet. There is evidence for interpretation of a broad high-energyband as transitions to states with positive JT energy stabilized
by pseudorotations cone states, and we suggest asimilar assignment for a high-energy absorption band in themonoanion.
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As we climb new heights
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We become more thoughtful!
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