Momentum Imaging in Atomic Collision Physics

• BREADTH : MICROMODEL OF ICPEAC

• WHAT IS IT?

• FOCUS: DOUBLE IONIZATION

ICPEAC 2003ICPEAC 2003

BREADTH: MODEL OF ICPEAC ?

ICPEAC 2003ICPEAC 2003

EVENT BY EVENT EVENT BY EVENT MOMENTUM IMAGING MOMENTUM IMAGING ION-ATOM COLLISIONSION-ATOM COLLISIONS

COLLISIONS IN MOTS COLLISIONS IN MOTS USE TO ANALYZE MOTUSE TO ANALYZE MOT

IONIZATION IONIZATION WITH INTENSE LASERWITH INTENSE LASER

PULSESPULSES

WITH SYNCHROTRONWITH SYNCHROTRONRADIATIONRADIATION

OF MOLECULES OF MOLECULES WHICH EXPLODEWHICH EXPLODE

Conceptual COLTRIMS

p

pp’

Projectile Electron Recoil

Single detectors

p

pB

E

Imaging

p

pp’

THE DETECTOR

The detectorThe detector

Well, not Well, not really, but really, but the idea is the idea is similarsimilar

CMS detector at FermilabCMS detector at Fermilab

Cold Target Recoil Ion Momentum SpectroscopyCold Target Recoil Ion Momentum Spectroscopy

EE

BB

COILSCOILS

POSITION AND POSITION AND TIME SENSITIVETIME SENSITIVEDETECTORSDETECTORS

P ALONG BEAM FROM TIMEP ALONG BEAM FROM TIMEP TRANSVERSE FROM POSITIONP TRANSVERSE FROM POSITION

REACTIONREACTION

THE BASIC DETECTOR

CHOOSE ONE OF EACH

EE

BB

COILSCOILS

POSITION AND POSITION AND TIME SENSITIVETIME SENSITIVEDETECTORSDETECTORS

LASER BEAMLASER BEAM

SYNCHROTRONSYNCHROTRONRADIATION RADIATION PHOTON BEAMPHOTON BEAM

ION BEAMION BEAM

(SUPERSONIC)(SUPERSONIC)JETJET

/4 /4

/4

/4

MOTMOT

BEAMBEAM TARGETTARGET

DETECTORDETECTOR

CLASSIC CONFIGURATION : IONS ON JETS

EE

BB

COILSCOILS

POSITION AND POSITION AND TIME SENSITIVETIME SENSITIVEDETECTORSDETECTORS

ION BEAMION BEAM

SUPERSONICSUPERSONICJETJET

VARIATION ONE: PHOTONS ON JETS

EE

BB

COILSCOILS

POSITION AND POSITION AND TIME SENSITIVETIME SENSITIVEDETECTORSDETECTORS

SUPERSONICSUPERSONICJETJETSYNCHROTRONSYNCHROTRON

RADIATION RADIATION PHOTON BEAMPHOTON BEAM

VARIATION TWO: LASERS ON JETS

EE

BB

COILSCOILS

POSITION AND POSITION AND TIME SENSITIVETIME SENSITIVEDETECTORSDETECTORS

SUPERSONICSUPERSONICJETJETLASER BEAMLASER BEAM

VARIATION THREE: ION BEAMS ON MOT

EE

BB

COILSCOILS

POSITION AND POSITION AND TIME SENSITIVETIME SENSITIVEDETECTORSDETECTORS

ION BEAMION BEAM

/4 /4

/4

/4

MOTMOT

VARIATION FOUR: LASER BEAMS ON MOT

EE

BB

COILSCOILS

POSITION AND POSITION AND TIME SENSITIVETIME SENSITIVEDETECTORSDETECTORS

/4 /4

/4

/4

MOTMOT

LASER BEAMLASER BEAM

Some typical momenta in the interaction

Momentum carried by photon:

E/c , c=137 in au. : 8 x 10 –3 a.u. for a 300 eV photon.

Momentum carried by a 10 eV electron ejected from atom:

0.86 a.u.

Momentum carried by 5 eV molecular C+ fragment:

90 a.u.

Momentum of thermal He atom at 300 K / Rb atom at 250 x 10 -6 K

4 a.u. .017 a.u.

Experimental resolution:

Recoils < 0.2 a.u. Electrons < 0.05 a.u.

The physicsLow energy collisions: Capture by highly charged ions

Ionization : continuum electrons

High energy collisions:

Small Z/v…photons

Fixed in space molecules: inner shells

Single electron processes

Two electron processes

Intense laser

Large Z/v

Large Z/v

Small Z/v…photons

Capture by highly charged ions

-500 0 5000.0

0.2

0.4

0.6 Over barrier to make..

H2

++

H2

+

Ele

ctric

Fie

ld (

a.u

.)

Time (a.u.)

Field from 25+ ion at v=.05 with b=7 a.u.

Electric field caused by a passing Xe 26+ ion

Q spectra for capture from He by Ar 16+ ions

0 10 20 30-4

-3

-2

-1

0

1

n=5n=6

n=8n=9

n=7

Ar 15+ + He

Ar 16+ + He

Ene

rgy

(a.u

.)

R (a.u.)

M.Abdallah, W.Wolff, H.E.Wolf, E.Y.Kamber,M.Stockli and C.L.Cocke, Phys.Rev.A 58, 2911(1998).

Q value versus Auger electron energy in double capture

G. Laurent , M. Tarisien , X. Flechard , et al., Nucl. Inst. Meth. (2003, to be published).

O 6+ on He at 138 keV

O 6+ + HeO 4+ (nl,n’l’) + He ++

O 5+ + e Auger

High resolution Q value spectra from capture by Ne 7+ from He at 0.35 a.u.

D.Fischer, B.Feuerstein, R.D.DuBois, R.Moshammer, J.R.Crespo-Lopez-Urrutia et al., J. Phys. B 35, 1369 (2002).

Momentum resolution 0.07 a.u.

pz of recoil

Q-value spectra from Ar 8+ on atomic hydrogen

Experiment:Erge Edgu-Fry, Ph.D.ThesisTheory: Lee and Lin, Close coupling AO

-10 0 10 20 30 40 500

100

200

300

400

500

600

700

800

fd ps

fd p s

n=8

n=7

n=6n=5Ar8++H, v=0.32 a.u.

cou

nts

Q(eV)

Relative populations (%)Experiment Theory

5s 8.1 8.55p 14.6 19.65dfg 29.8 43.4Sum 5 52.5 71.66s 3.3 13.26p 32.5 6.36dfg 10.4 8.9Sum 6 46.3 28.4

MOTRIMS Van der Poel

M. van der Poel, C. V. Nielsen, M.-A. Gearba, and N. Andersen, Phys. Rev. Lett. 87, 123201 (2001).

Frauhenhofer diffraction in capture from Na by Li+

M.Van der Poel Ph.D. thesisOrsted Institute, Univ. Copenhagen

~ 10 -6 rad

MOTRIMS results: O 6+ on Na capture

J.W. Turkstra, R. Hoekstra, S. Knoop, D. Meyer, R. Morgenstern, and R. E. Olson, Phys.Rev.Lett. 87, 123202 (2001).

Experiment

CTMC

KSU MOTRIMS Cs+

R. Brédy, H. Nguyen, H. A. Camp, X. Flechard and B. D. DePaola, J.R.Macdonald Laboratory, Kansas State Univ.

-2.5 -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5

0.0005

0.0010

6 keV Cs++Rb(5s),Rb(5p) Cs*+Rb+

5p-5d

5s-6p

5s-6s

5p-6p

5p-6s

2.000

3.295

5.429

8.944

14.74

24.28

40.00

65.90

108.6

178.9

294.7

485.6

800.0

Q value (eV)

Sca

tterin

g A

ngle

(ra

d)

-3 -2 -1 0 1 2 30

5

10

15

20

Q Value (eV)

TAC

Tim

e (

s)

5.000

6.776

9.183

12.44

16.86

22.85

30.97

41.97

56.88

77.09

104.5

141.6

191.9

260.0

-3 -2 -1 0 1 20

5000

10000

15000

X 10

Na(4d)Na(3d)

Na(4s)

Na(3p) Na(3p)Capture from Rb(5s)Capture from Rb(5p)

Na(3s)

Cou

nts

Q value (eV)

KSU MOTRIMS Na+

R. Brédy, H. Nguyen, H. A. Camp, X. Flechard and B. D. DePaola, J.R.Macdonald Laboratory, Kansas State Univ.

Na+ capturing from Rb(5s) and Rb(5p)

5s-3p 5p-3p

laser off

laser on

T. G. Lee, H. Nguyen, X. Flechard, B. D. DePaola, and C. D. Lin Phys. Rev. A 66, 042701 (2002)   

The physicsLow energy collisions: Capture by highly charged ions

Ionization : continuum electrons

High energy collisions:

Small Z/v…photons

Fixed in space molecules: inner shells

Single electron processes

Two electron processes

Intense laser

Large Z/v

Large Z/v

Small Z/v…photons

Ionization: continuum electrons

Projectile

Recoil

In plane

5 keV

10 keV

15 keV

Doerner et al,Phys.Rev.Lett. 77,4520 (1997)

Continuum electrons for fixed scattering plane

p on He

Electron spectra for He+ on He

M.A.Abdallah et al., Phys.Rev.81, 3627 (1998).

He+

He+

e-0.5

0.0

0.5

0.0 0.5 1.0

-0.5

0.0

0.5

-0.5

0.0

0.5

v ey /v

p

-0.5

0.0

0.5

0.0 0.5 1.0

-0.5

0.0

0.5

vez

/vp

0

50

100

150

-1.0 -0.5 0.0 0.5 1.0

tr mom=

0-1.5 a.u.

10 keV/u He+ + He (v

p = 0.64 a.u.)

0

50

100

150

200

250 tr mom=

1.5-3 a.u.

0

50

100

150

200 tr mom=

3-5 a.u.

coun

ts

0

100

200

300 tr mom=

5-10 a.u.

-1.0 -0.5 0.0 0.5 1.00

50

100tr mom=

10-15 a.u.

vey

/vp

1 eV

Electron spectra for Transfer Ionization for He++ on He

A.F.Afaneh, R Doerner, L Schmidt, Th Weber, K E Stiebing, O Jagutzki and H Schmidt-Boecking, J. Phys. B 35 L229 (2002).

Cou

nts

Ve,

y /

Vp

Ve, z / Vp

Pt= 8-16a.u.

Pt= 4- 8a.u.

Pt= 2- 4a.u.

Pt < 2.0a.u.

0.0 0.5 1.0 1.5

(e)

-0.5

0.0

0.5 (a)

0.0 0.5 1.0 1.5

-0.5

0.0

0.5 (b)

-0.5

0.0

0.5 (c)

0.0 0.5 1.0 1.5

-0.5

0.0

0.5 (d)

(f)

(g)

0.0 0.5 1.0 1.5

(h)

0

100

0

200

0

300

0

200

The physicsLow energy collisions: Capture by highly charged ions

Ionization : continuum electrons

High energy collisions:

Small Z/v…photons

Fixed in space molecules: inner shells

Single electron processes

Two electron processes

Intense laser

Large Z/v

Large Z/v

Small Z/v…photons

Single electron processes

Electron ejection by charged particle: large q vs small q

Small q………. “optical limit”Large impact parameterProjectile delivers energy onlySets positive charge in Oscillation against negative charge

Large q exchange with one electronRest of atom is spectator(Rutherford and Marsden)

V~ e i q.r

Single photoionization recoils

80 eV Single Ionization of He

krecoil ion = -ke

h R. Doerner et al., Phys. Rev. Lett. 76, 2654 (1996).

Very low perturbation He single ionization:electron – recoil momentum balance

1 GeV/u U 92+on He

Moshammer et al.,Phys.Rev.Lett. 79, 3621 (1997).

Kinematically complete: electron spectra for experimentally controlled q

Photons

Charged particles

q “binary”“recoil”

He+e-q

M.Schulz, R.Moshammer, D.H.Madison, R.E.Olson et al., J.Phys.B 34, L305 (2001).

A.Dorn, R.Moshammer, C.D.Schroeter, et al., Phys.Rev.Lett.82,2496(1999).

100 MeV/u C 6+ q=.88 a.u.

3 keV electronsq=1.5 a.u.

M.Schulz et al., Nature 422, 48 (2003)

Is everything understood for single ionization in the low perturbation limit?

100 MeV/u C 6+ on He

Single ionization electron momentum distributions

Experiment

Calculation (Madison)

Conclusion: nuclear momentumtransfer not being treated correctly.

High perturbation He single ionization:electron-recoil momentum balance

3.6 Mev/ Se 28+ on He

Moshammer et al.,Phys.Rev.A 56,1351 (1997).

The physicsLow energy collisions: Capture by highly charged ions

Ionization : continuum electrons

High energy collisions:

Small Z/v…photons

Fixed in space molecules: inner shells

Single electron processes

Two electron processes

Intense laser

Large Z/v

Large Z/v

Small Z/v…photonsTwo electron processes

Two electron removal: how to do it?

TS2 TS1

L.H.Andersen, H.Knudsen, P.Hvelplund, et al., Phys.Rev.Lett. 57, 2147 (1986).

High perturbation He double ionization: electron pair –recoil momentum balance

A.N.Perumal, R.Moshammer,M.Schulz and J.Ullrich, J.Phys.B 35, 2133 (2002).

3.6 MeV/u Au 53+ on Heq

He++

ee

Double ionization:Electron pair ejection

Single ionization

3.6 Mev/ Se 28+on He Moshammer et al.,Phys.Rev.A 56, 1351 (1997).

The small perturbation case

TS1 collision Shakeoff

Small Z/v or photon

Electron distributions: photodouble ionization of He

k+ = k1+k2

k- =(k1-k2)/2

Jacobi

k1,k2

Lab

k1

k2

k+

k-

selections rules A=0 implies electrons in state

E1 selection rules plus ee repulsion;No back to back, no parallel emissionOpening angle around 120 degrees

J S Briggs and V Schmidt, J.Phys.B 33, R1 (2000).

1 eV

Photodouble ionization of He

Electron momenta

20 eV excess energy

k+ = k1+k2

k1, k2

k- = (k1-k2)/2

H. Braeuning, R. Doerner, C.L. Cocke, M.H. Prior et al., J. Phys. B30, L649 (1997).

Can we get out of the “collective motion” region into the “single particle motion” region?

A.Knapp, M.Walter, Th. Weber, A.L.Landers, et al., .Phys.B L521 (2002).

Photodouble ionization at 529 eV photon energy

A.Knapp, A.Kheifets, I.Bray, Th.Weber, A.L.Landers et al., Phys.Rev.Lett.89, 033004 (2002).

The “shaken off” electron

Experiment Theory (CCC:Kheifets)

Soft electrons are shaken off

Harder electrons are generated in ee collisions

2eV

30eV

fastslow

Photodouble ionization of H2: the relaxation of the dipole selection rule

Thorsten Weber ,Ph.D. thesis, Univ. Frankfurt (2003) and Th. Weber et al., in preparation (2003) .

Helium:Node on cone

H2: Node is There but relaxed

Node on cone where no dipole moment of systemalong polarization vector

Walter and Briggs, PRL

85, 1630 (2000).

Photodouble ionization at 529 eV photon energy

A.Knapp, A.Kheifets, I.Bray, Th.Weber, A.L.Landers et al., hys.Rev.Lett.89, 033004 (2002).

The “shaken off” electron

Experiment Theory (Kheifets)

Soft electrons are shaken off

Shaken electron distribution from transfer ionization

H. Schmidt-Böcking, V. Mergel, R. Dörner et al., Europhys. Lett., 62 , 477 (2003) .

300 keV protons on He: capture one, other leaves

Correlated “Shakeoff” Shi and Lin

T.Y.Shi and C.D.Lin, Phys.Rev.Lett. 89, 163202 (2002).

The probability for ionization The momentum of the shaken electron

High velocity TI: CRYRING

H.T. Schmidt, A. Fardi, R. Schuch, et al., Phys. Rev. Lett., 89, 163201-3 (2002) and Henning Schmidt, private comm. 2003

recoil pzfast protons on He , capture one, make He++

Charged particle “dipole” double ionization

Photons

k+ =k1+k2

k- =(k1-k2)/2

Jacobi

k1,k2

Lab

Charged particles

q “binary”“recoil”

“recoil” “binary”

qHe++

ee

Electron distributions: double ionization of He DATA

“recoil”

“binary”

CCC Kheifets

Photodouble ionization

Experiment

A. Dorn, A.Kheifets, C.D.Schroeter, B.Jajjari et al., Phys.Rev.Lett.86, 3755(2001

q=0.6a.u.

2 keV electrons

q

1

2

1

2

The physicsLow energy collisions: Capture by highly charged ions

Ionization : continuum electrons

High energy collisions:

Small Z/v…photons

Fixed in space molecules: inner shells

Single electron processes

Two electron processes

Intense laser

Large Z/v

Large Z/v

Small Z/v…photons

Fixed in space molecules:Inner shells

Illuminating molecules from within

hhvv + CO + CO CO CO++ (1s (1s-1-1) + e) + e--(photoelectron) (few eV)(photoelectron) (few eV) (10 (10 –17–17 s) s) CO CO 2+2+ + e + e--(Auger) (high energy)(Auger) (high energy) (10 (10 –14–14 s) s)

CC++ + O + O + + (10 (10 –13–13 s) s)

University Frankfurt: Reinhard Dörner,Horst Schmidt-Böcking,Thorsten Weber,Alexandra Knapp, Till Jahnke, Lothar, Schmidt, Sven Schössler, Harald Bräuning, Achim Czasch

Kansas State University C. Lewis Cocke, Timur Osipov, Ali

Alnaser

LBNL Michael H. Prior, Jürgen Rösch, Andre Staudte

Western Michigan U. Allen Landers

Guest: Amine Cassimi (Ganil/Ciril)

What determines the angular distribution of the photoelectrons?

Polarization of incident Radiation : p-wave Direction of incident radiation:(Non-dipole effects?)

Depends on molecular orientation

Interference of wave Scattered on other center

e iq.r

Shape resonance inpotential well of molecule

Depends on external radiation

The sigma (f-wave) resonance in CO

is the photoelectron momentum vectoras you scan the photon energy

A.Landers, in “Photonic, Electronic and Atomic Collisions”,

ed. J.Burdoerger et al., p. 149 (Rinton, Princeton, 2002).

Steps of process and energeticsC2H2

+

CC22HH22

CC22HH22++++

h= 309 eV

Photoelectron

AugerAuger

D.Duflot et al., D.Duflot et al., J.Chem.Phys.10J.Chem.Phys.102,1(1995).2,1(1995).

KER spectrumKER spectrumT.Osipov,KSUT.Osipov,KSU

10 20 10 20

KER Vinylidenechannel

Auger electron angular distributions in CO

Th. Weber, M.Wedkenbrock, M.Balser, L.Schmidt, O.Jagutzki et al., Phys.Rev.Lett. 90, 153003 (2003).

Molecule does NOT remember how the hole was made

But for some channels the distribution is very sharp, even Headlight-like!

Is there an f-wave resonance in C2H2?

B.Kempgens et al., PRL 79, 35 (1997).

The f-wave enhancement in C2H4

Osipov, KSU, 2003

Comparison of C2H2 and C2H4

Recoil momentum spectra of near symmetric breakup for mass 24 or 26

Acetylene/Vinylidene

Can the angular distributions tell about the fragmentation dynamics?

EXPTTh.Weber et al., JPB 34, 3669 (2001).

THEORYR.Diez Muino, D.Rolles, F.J.Garcia de Abajo, F.Starrost, W.Schattke, C.S.Fadley and M.A.Van Hove, J.Electron Spec.Relat.Phenom.99,114(2001).

Use fragments to align molecule, look at Use fragments to align molecule, look at photoelectron distributionsphotoelectron distributions

PhotoemissionC2H2

+

10-17 sec

Slow?Slow?Fast?Fast?

CH2+ C+ CH+ CH+

AugerC2H2

++

10-14 sec

Lose molecule-photoelectron angleLose molecule-photoelectron angle Keep molecule-photoelectron angleKeep molecule-photoelectron angle

Use photoelectrons to align molecule, look Use photoelectrons to align molecule, look at fragmentation dynamicsat fragmentation dynamics

Photoelectrons for A and V

Rotation angle measured: 20 degreesRotation angle measured: 20 degrees

Rotation required by mass Rotation required by mass rearrangement: 21.6 degreesrearrangement: 21.6 degrees

Conclusion: Data is consistent with Conclusion: Data is consistent with

instantaneousinstantaneous rearrangement. rearrangement.

What is the longest time it could take ? What is the longest time it could take ? If additional 10 degrees,If additional 10 degrees,

L=2 from Auger decay, calculate L=2 from Auger decay, calculate omega(rotational) times rearrangement omega(rotational) times rearrangement time 10 degrees, gettime 10 degrees, get

Rearrangement time shorter than 60 fs. Rearrangement time shorter than 60 fs.

Calculated vibrational period for Calculated vibrational period for bending mode 10 fs. bending mode 10 fs.

The physicsLow energy collisions: Capture by highly charged ions

Ionization : continuum electrons

High energy collisions:

Small Z/v…photons

Fixed in space molecules: inner shells

Single electron processes

Two electron processes

Intense laser

Large Z/v

Large Z/v

Small Z/v…photons

Intense laser

B.Walker,B. Sheehy, L.F. DiMauro, B.Walker,B. Sheehy, L.F. DiMauro, P.Agontino, K.J.Schafer and K.C.Kulander, P.Agontino, K.J.Schafer and K.C.Kulander, Phys.Rev.Lett.73,1227(1994).Phys.Rev.Lett.73,1227(1994).

The Knee

SequentialTS2

Non-sequentialTS1

Sequential ionization Non-sequential

TS1, ShakeoffTS2 - like

Momentum spectra for He and Ne ions

Th. Weber, M. Weckenbrock, A. Staudte, L. Spielberger, O. Jagutzki, V. Mergel, F. Afaneh, G. Urbasch, M. Vollmer, H. Giessen, and R. Dörner, Phys.Rev.Lett. 84, 443 (2000).

R. Moshammer, B. Feuerstein, W. Schmitt, A. Dorn, C. D. Schröter, and J. Ullrich ,H. Rottke, C. Trump, M. Wittmann, G. Korn, K. Hoffmann, and W. Sandner, Phys.Rev.Lett. 84, 447 (2000).

2.9 1014 W/cm2

3.8 1014 W/cm2

6.6 1014 W/cm2

He Ne

Sequential ionization Non-sequential

Rescattering

Transition from NS to sequential for Ar

Th.Weber, M.Weckenbrock, A.Staudte, L.Spielberger, O.Jagutzki, V.Mergel, F.Afaneh, G.Urbasch, M.Vollmer, H.Giessen and R.Dörner, J.Phys.B 33, L127

(2000).

Increasing laser intensity

Below the knee:NS

Above the knee:SI

Ar 2+ p1 vs p2 along polarization vector

Th. Weber, H. Giessen, M. Weckenbrock, G. Urbasch, A. Staudte, L. Spielberger, O. Jagutzki, V. Mergel, M. Vollmer and R. Dörner , Nature 405, 658 (2000). 

p1

p2

p2

p1

Off diagonal Ar 2+ momentum spectrum

B.Feuerstein, R.Moshammer, D.Fischer, A.Dorn, C.D.Schröter, J.Deipenwisch, R.R.Crespo Lopez-Urrutia, C.Höhr, P.Neumayer, J.Ullrich, H.Rottke, C.Trump, M.Wittmann, G.Korn and W.Sandner, Phys.Rev.Lett. 87, 043003 (2001).  

classicallyallowed

excitationkinematics

Comparison of Ar and Ne p1 vs.p2 plotNe Ar

R.Moshammer, J.Ullrich, B.Feuerstein, et al., Optics Express 8, 358 (2001).

B.Feuerstein, R.Moshammer, D.Fischer, et al., Physs.Rev.Lett. 87, 043003 (2001).

Classically allowed rescattering ionization

Excitation plus laser ionization

R.Moshammer, J.Ullrich, B.Feuerstein, B.Fischer, A.Dorn, C.D.Schröter, J.R.Crespo Lopez-Urrutia, C.Höhr, H.Rottke, C.Trump, M.Wittmann, G.Korn K.Hoffmann and W.Sandner, J.Phys.B 36, L113 (2003).

. R.Moshammer, B.Feuerstein, D.Fischer, A.Dorn, C.d.Schroeter, J.Deipenwisch, J.R.Crespo Lopez-Urrutia, C. Hoehr, P.Neumayer and J.Ullrich, Optics Express 8, 358 (2001).

Ne double ionization electron energy spectra

Ne single ionization : dip in the middle

R.Moshammer, J.Ullrich, B.feuerstein, D.Fischer, A.Dorn, C.D.Schroeter, J.R.Crespo Lopez-Urrutia, C.Hoehr, H.Rottke, C.Trump, M.Wittmann, G.Korn and W.Sandner, to be published.

. R.Moshammer, B.Feuerstein, D.Fischer, A.Dorn, C.d.Schroeter, J.Deipenwisch, J.R.Crespo Lopez-Urrutia, C. Hoehr, P.Neumayer and J.Ullrich, Optics Express 8, 358 (2001).

-3 -2 -1 0 1 2 30

2000

4000

6000

8000

coun

ts

pion ||

[a.u]

semiclassical model(with rescattering)J. Chen, C. Nam PRA (2002) 053415

I = 0.7.1015 W/cm2

The physicsLow energy collisions: Capture by highly charged ions

Ionization : continuum electrons

High energy collisions:

Small Z/v…photons

Fixed in space molecules: inner shells

Single electron processes

Two electron processes

Intense laser

Large Z/v

Large Z/v

Small Z/v…photons

Intense laser on D2

Time of flight spectrum for laser on D2

time of flight [ns]

cou

nts

8 x 1014 W/cm2

t=100 fs

dd++ DD22++

Energy in eV of dEnergy in eV of d++

Polarization along time direction

What is all this structure?

Frazinski et al, PRL 83, 3625Frazinski et al, PRL 83, 3625

Bond softening : dissociationBond softening : dissociation

Zavriev et al., PRA , 1992.

This is what it is……….

time of flight [ns]

cou

nts

8 x 1014 W/cm2

t=100 fs

dd++ DD22++

Energy in eV of dEnergy in eV of d++

Bond softening and ATIBond softening and ATI

CREI double ionizationCREI double ionization

RescatteringRescattering

Evidence for rescattering double ionization in D2

Energy release of d+ pairs versusNet momentum of system

Circular polarization

Linear polarization

The rescattering component

d+ sum energy spectra from Laser + D2 > d+ + d+ + 2e

Linear Circular

Difference

0 20 Energy (eV)

0 20 Energy (eV) 0 20 Energy (eV)

RES

RES

CE

CE = Coulomb explosion via CREIRES = rescattering CE

d+ sum energy spectra from Laser + D2 > d+ + d+ + 2e

Linear Circular

Difference

0 20 Energy (eV)

0 20 Energy (eV) 0 20 Energy (eV)

RES

RES

CE

CE = Coulomb explosion via CREIRES = rescattering CE

The schematic

Niikura et al., Nature 417,917(2002)

The model and the clock

Electrons return at 2/3 of period plus integral number

of periods of 2.6 fs

CREI

Alnaser et al. Tong and Lin

How does the laser pulse compare to the pulse a passing charged particle makes?

-500 0 500

-0.4

-0.2

0.0

0.2

0.4

0.6Over barrier to make..

H2

++

H2

+

Ele

ctri

c F

ield

(a

.u.)

Time (a.u.)

Field from 25+ ion at v=.05 with b=7 a.u.

Field from 8 x 10 14 W/cm2 , 8 fs pulse

Comparison of field from laser pulse with that for a passing Xe 26+ ion

Summary

• Recoil momentum spectroscopy is widely applicable

• Collisions and pulses have much in common

CREDITS

The workersApologies to the theorists..J.Briggs, J.Feagin, A.Kheifets,R.E.Olson, C.D.Lin, ….

Ryan Kinney Natasha Maydanyuk

AhmadHasan

MichaelSchulz

Univ. Missouri at Rolla

Kansas State Univ.

M.Zamkov C.Wang M.Benis S.Voss L.Cocke A.Alnaser T.Osipov B.Shan C.Maharjan

A. Staudte, M. Trummel, T. Jahnke, M. Weckenbrock, Th. Weber, M. Hattaß, R. Grisenti, M. Schöffler, M. Balser, M. Odenweller, A. Gumberidze, L. Schmidt

J. Nickles, Th. Jalowi, M. Kaesz, R. Dörner, A. Knapp, C. Wimmer, J. Titze, H. Schmidt-Böcking

Univ. Frankfurt

Artem Rudenko, Vitor Bastos de Jesus, Robert Moshammer,

Daniel Fischer, Conny Höhr, Joachim Ullrich,

Christina Dimopoulou, Alexander Dorn, Bernold Feuerstein

MPI Heidelberg

CRYRING

Afshin Fardi

Jens Jensen

Henning SchmidtHenning

ZettergrenPeter

ReinhedHenrik

Cederquist

Thorsten Weber, Ph.D.R.Dörner, Boss

Part of the ALS Bunch

Osipov, Hertlein, Jahnke, Schriel, Cole, whole Dörner family, Prior, Benis

The EndThe End

The N2 movie

The f-wave enhancement in C2H4

Ovipov, KSU2003

Niikura et al., Nature 417,917(2002)