Controlling Matter with Light

Robert J. GordonUniversity of Illinois at Chicago

DUV-FEL Seminar

January 6, 2004

NSF, DOE, PRF, UIC/CRB, Motorola

Outline

• Dissociative Ionization

• Molecular Optics

• Coherent Control

• Material Processing

Photodissociation of C6H5I at 266 nm

J. Phys. Chem. A 105, 2001 (2001)

Mechanism at 266 nm

2/3,2/12

56032 *, PIHCnQhn

Outer Feature

Inner Feature

2/32

5611

12 *,~*, PIHCnQShn

Photodissociation of C6H5I at 532 nm

J. Phys. Chem. A 105, 2001 (2001)

Photodissociation of I2

532 nm

564 nm

559 nm

575 nm

PRL 86, 2241 (2001)

Kinetic Energy of Iodine

556.0 nm

574.7 nm

Dissociative Ionization

Dissociative Ionization of H2

J. Phys. B 30, 2319 (1997) JCP 104, 8449 (1996)

Possible FEL Experiments

• 90 – 100 nm single photon excitation

• Pump-probe photoelectron-photoion coincidence (Hayden)

• Photoelectron angular distributions of aligned molecules

Manipulating Molecules With Light

Alignment

Orientation

Deflection

Focusing

Trapping

Interaction with a Focused Laser

Beam

Intensity

Potential

Force

Dipole Interaction

Gaussian electric field )(),(

22 /0 tfeEtrE r

Dipole potential

22//

2 sincos),(2

1cos),(),( trEtrErU

r deflection & focusing

alignment & orientation

Dipole Force

22 /0

reEE Gaussian field

22 /220//4

1 reEU Induced potential

U0(K) = 15 α//(3) I(TW/cm2)

Deflecting Molecules in Different MJ States

E

|M| = J M = 0

Li2

Seideman, 107, 10420 (1997)

Stark Shift

CCD

1064 nm 358 nm

tof msMCP

Molec. Beam

Apparatus

CS2 Deflection

Yan Du

Joyce

Joyce Willig

Sujatha Unny

/n

6

/n

6 10

3

l n3

- l-2

e-

Seideman, JCP 111, 4397 (1999).

Dynamic Polarizability

Molecular Mirror

Classical forced oscillator:

teEkrrm cos0

220

0 cos

tEm

e

r

Sign reversal at high frequency

Possible FEL Experiments

• Deflect molecules in high Rydberg states

• Use a near-resonant deflection field

F. Crim

Passive Control of Chemical Reactions

Active Control of Chemical Reactions

Interference Between Competing Paths

 P = P1 + P2 + P12

 P = |f1 + f2|

2

 = |f1 |

2 + |f2|2 + f1f2

* + f1*f2

2

31ieffP

cos2 3131 PPPP

13 3

Shapiro, Hepburn, and Brumer, Chem. Phys. Lett. 149, 451 (1988).

Coherent Phase Control of Bound-Bound Transitions

Apparatus

Langchi Zhu

Phase Tuning

001

033

13

//

3

PPnncl

Controlling Branching Ratios

SSSSS PPPP 131331 cos2

S = A

S = B

JPC

The Phase Lag

kdgDkESkESDgePSiS ˆˆˆ )3()1(

1313

The Channel Phase

The Phase Lag

BABA 1313),(

Molecular Phase

Resonance Phase

Phase Lag Spectrum of HI

Coupling Schemes

CH2=CHCl + 3, 31

Cl

H

HCl

H2

VCl Experimental Setup

Polarizer

Nd:YAG Laser532 nm

/2 Plate

Excimer Laser

308 nm Dye Laser

404.6 nm

TOF/MS

3=31

1

Hg TriplingCell

Vishal Barge

Possible FEL Experiment

• Coherent phase control of the ionization and dissociation of the Q1 states of H2

Wave Packet Control

Possible FEL Experiment

• Pump-probe study of time-resolved intersystem crossing in pyrazine

• Wave packet control of ISC

Pyrazine Intersystem Crossing

Ion

S1

S0

T1

C4N2H4

Photoelectron Spectrum of Pyrazine

JCP 95, 2237 (1991)

Material Processing

• Biomedical applications

• Microfluidics

• Nano-fabrication

Machining Collagen Scaffolds

Micro-grooves Mesenchymal Stem Cells

Biocompatibility of Collagen Scaffold

Possible FEL Experiment• Subdiffraction nanomachining

Appl. Phys. B 77, 25 (2003)