Dancing a Waltz with Fullerene

8/3/2019 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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- -

---


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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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Dancing a Waltz with Fullerene

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