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Low-density matter with synchrotrons and time-resolved experiments with FELs Maria Novella Piancastelli Sorbonne Universits, UPMC Univ Paris 06, CNRS, Laboratoire de Chimie Physique-Matire et Rayonnement, Paris, France Department of Physics

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Low-density matter with synchrotrons and time-resolved experiments with FELs

Maria Novella Piancastelli

Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Chimie Physique-Matière et Rayonnement, Paris, France Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden

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Photon is
Adsorbed
Elastically

Scattered

Inelastically

Scattered

Incident photon interacts with electrons

Electron is
Emitted
Excited
De-excited

Cross Sections

Photon Interaction

Below 100 keV Photoelectric and elastic cross section dominate

Spectroscopy-Scattering

SLIDE 3

EMITTED PARTICLE

Elastic Scattering X-Diffraction
Inelastic Scattering X-ray Emission Spectroscopy
Electron Emission

Photoelectron Spectroscopy

NO EMITTED PARTICLE

Photon Adsorbed

X-ray Absorption Spectroscopy

Detected Particles

SLIDE 4

Spectroscopy hn

Valence electrons Chemical Bonding Core electrons Non interacting Ionization Photoelectron Spectroscopy

SLIDE 5

Methods

X-ray Diffraction
Photoelectron Spectroscopy (PES)

Core level electron spectroscopy Valence band photoemission Resonant photoemission

X-ray Absorption Spectroscopy (XAS)

Near Edge X-ray Absorption Spectroscopy (NEXAFS) Extended X-ray Absorption Fine Structure (EXAFS)

X-ray Emission Spectroscopy (XES)

Resonant Inelastic X-ray Scattering (RIXS)

SLIDE 6

Selected examples:

Resonant photoemission Ultrafast dynamics Young’s double slit-type interference Doppler effects

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Electron Spectroscopy

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X-ray Absorption Spectroscopy of N20

ion mass A+ B+ AB+

Ionic products

Auger

SLIDE 9

Decay Processes in Core-Excited N2O

M N Piancastelli et al., J.Phys.B: At.Mol.Opt.Phys. 40, 3357(2007)

SLIDE 10

O = N ≡ N

N≡N=O

7s 6s 3p 1p 2p

LUMO HOMO

n top of the Ncentral 1s-> 3p resonance
n top of the Nterminal 1s-> 3p resonance
n top of the O 1s-> 3p resonance

SLIDE 11

Nuclear Dynamics of core-excited systems

Possible mechanisms

f nuclear dynamics:
ultrafast dissociation
geometry change

– e.g. bending, twisting

conformational changes

SLIDE 12

Auger resonant Raman conditions: Photon bandwidth much narrower than the natural lifetime width of the intermediate state

Core-hole clock

(ΔT) (ΔE) ≥ ℏ/2

SLIDE 13

  



2 2

 c

duration time

 

SLIDE 14

Ultrafast dissociation

Nuclear Dynamics of core-excited systems

SLIDE 15

I.Hjelte, M.N.Piancastelli, R.F.Fink, O.Björneholm, M.Bässler, R.Feifel, A.Giertz, H.Wang, K.Wiesner, A.Ausmees, C.Miron, S.L.Sorensen and S.Svensson, Chem.Phys.Lett. 334, (2001) 151

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M. N. Piancastelli, G. Goldsztejn, T. Marchenko, R. Guillemin, R. K. Kushawaha, L. Journel, S.

Carniato, J.-P. Rueff, D. Céolin and M. Simon, J.Phys.B: At.Mol.Opt.Phys. 47, (2014) 124031

CH3Cl Cl K-edge

SLIDE 24

SLIDE 25

Young´s double slit interference in photoemission

SLIDE 26

SLIDE 27

Calculations by P.Decleva

SLIDE 28

R.K. Kushawaha, M. Patanen, R. Guillemin, L. Journel, C.Miron,

M. Simon, M.N.Piancastelli and P. Decleva, PNAS 110, (2013) 15201

SLIDE 29

C2s sigma_g / sigma_u cross section ratio

photon energy (eV)

200 400 600 800 1000

cross section ratio

0.5 1.0 1.5 2.0 2.5 C2H2 C2H4 C2H6

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Atomic Auger Doppler effects upon emission of fast photoelectrons

SLIDE 34

M.Simon, R.Püttner, T.Marchenko, R.Guillemin, R.K. Kushawaha, L.Journel, G.Goldsztejn, M.N.Piancastelli, J.M. Ablett, J.-P.Rueff and D.Céolin, Nature Comm. 5, 4069 (2014)