Dynamics of clusters and moleculesin strong electromagnetic fields:

A TDDFT-MD approach

Ionization

Environment

Time-resolved dynamics

Laser

Projectile

Fondamental studies of mechanisms of irradiationand response of clusters coupled with environment

model-potential electrons

TDDFT-MD

Gen. QM/MMDyn. polar. TDCI

Sta

tics

Dyn

am

ics

ElectronsEnvironment

Methods on the market

Car-Parinello, BO/MDCar-Parinello, BO QM/MM

model-potential electrons

Today: CNOH molecules

+ H2O "environment"

Nan@Ar,Ne,Kr@ MgO

Nan

n valence e-

n ions (Na+)

TDLDA + ADSIC MD-TDDFT(LDA)non-adiab. dynamics

(≠BO)• explicit• pseudopotentials

TDDFT-MD

laserprojectile

Today, ions are: C4+, O6+, N7+, H+

Numerical details

represented on 3D grid: 483, 643, 723, 963, …

Goedecker-like (non-local)

dt = 0.5 as

50 fs for H2O

643 54 h 70h

962 x 72 138 h 234 h

fixed ions moving ions

propagation: time-splitting

Verlet algorithm

box size

Home-made codes

(Time-resolved) observables

from electrons: optical responsecloud deformation, shape, localizationionization

> number of emitted e-

> kinetic E spectrum of emitted e-

> angular distribution of emitted e-

> level depletion

from ions: potential and kinetic (temperature) Eglobal deformation and shapebond lengths, energies

Today: • projectile + H2O• laser + (H2O) H3O+

• laser/proj. + C2H4

water = electronic insulator gap 10 eV

0.1 au

threshold

Why TDLDA-MD ?

projectile + H2O

charg

e

velocity0

adiab.

sudden

cf. J. Kohanoff

adiab.

Why TDLDA-MD ?ch

arg

e

velocity0

"fixed e-" +

ionic MD

suddene- TDDFT

+fixed ions

??

Which theory for:dynamical description of

irradiation and response of

electrons and ions ?

?

?

H+ + H2O

C + H2O

H+ + H2O, low v

C + H2O, high v

Laser irradiation of (H2O)H3O+

Epol

I0=1013W/cm2

FWHM=20 fsfrequency scan

IP=-20.6 eV

off-resonant but...

off-resonant

vibrations

2

C2H4 : optical response

IP: -11.7 eV

6.8 eV

Yabana, Bertsch (2001)

Fourier Transform

8.16 eV 136 eV

Laser pol.I = 1013 Wcm-2

FWHM = 20 fs

C2H4 : laser irradiation

below resonances on resonance well above resonance

Ionization (level depletion) from a given electronic levelCompare cases with similar (small) net ionization

C2H4 : ionization mechanisms

Ionization

Environment

Time resolved dynamics

Laser

Projectile

Dynamical description of irradiationand response of electrons and ions with coupling to environment

Irradiation

of

clusters

and

molecules

by intense

electro-

magnetic

fields

Environment- Hierarchical model Dynamical QM/MM- Na@Ar, Kr, Ne - Na @ MgO - Na@H2O in the oven- C, N, O @ H2O in near future- C, N, O @ H2O @Ar in future

Dynamics of ionization- Self Interaction problem (SIC)- Benchmark TDSIC calculations - Simple approximations in the oven- Dynamical correlations in the future (electronic transport)

Time resolved dynamicsKey importance of non adiabaticelectron-ion dynamics for understanding mechanisms

Thanks toE. Suraud, P.-G. Reinhard,Z.P. Wang,U. Ndongmouo, J. MessudS. Vidal, andyou for your attention !