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W I S S E N T E C H N I K L E I D E N S C H A F T

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17. Januar 13

Name und OE, Eingabe über > Kopf- und Fußzeile

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Thursday, 2014-06-19Florian Lackner

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Helium droplet assisted preparation of…

Molecules[1,2,3]

0.1 nm 1 nm 10 nm 100 nm

Clusters Nanowires

[1]…Science 273, 629-631 (1996)[2]…Phys. Rev. Lett. 100, 063001, (2008) [3]…J. Phys. Chem. A 117, 13719 (2013)

Volk et al. J. Phys. Chem. 138, 214312 (2013)

Thaler et al., submitted manuscript (2014)

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RbSr molecules

X2Σ+ ground state: electric and magnetic dipole moment


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interesting for ultracold molecular physics[8]

RbSr has not been characterized experimentally…

… but extensively by theory because of increasing interest in RbSr [9,10,11,12,13]

[9]…Ẑuchowski et al. arXiv:1402.0702 (2014)[10]…Phys. Rev. Lett. 105, 153201 (2010)

[11]…Phys. Rev. A 88, 023601 (2013)[12]…Phys. Rev. A 82, 042508 (2010)[13]…Lackner et al. submitted manuscript (2014)

[8]…Phys. Rev. A 88, 023601 (2013)

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Production of RbSr Molecules on HeN


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HeN

Pickup

Rb Sr

Source conditions: 15 K / 60 bard ~ 8 nm

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Spectroscopic Methods


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Resonant two-photon ionization (R2PI) spectroscopy

Laser induced fluorescence (LIF) spectroscopy

Dispersed fluorescence (DF) spectroscopy

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RbSr on HeNTime-of-flight mass spectra

Monomers Dimers and RbSr

mass [amu]mass [amu]

ion

sig

na

l [a

rb.

u.]

ion

sig

na

l [a

rb.

u.]

Krois et al. in preparation

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RbSr Potential Energy CurvesMRCI calculations


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For details see: talk FC07Friday 10:07 AMJohann Pototschnig

X2Σ+

RbSr-HeN:only X2Σ+ (ν" = 0) is populated (0.37 K)

Lackner et al. submitted manuscript (2014)

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RbSr-HeN Excitation SpectrumTheory vs. experiment


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R2PI spectroscopy

Lackner et al. submitted manuscript (2014)

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42Σ+ state: Te = 14006(4) cm-1

ωe = 86(3) cm-1 ωexe = 1.2(0.7) cm-1

42Σ+←X2Σ+ Transition Vibrationally resolved


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R2PI

LIF

Information onfree RbSr molecules

Insight intoRbSr-HeN

Krois et al. in preparation

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…desorb from the droplet upon laser excitation (42Σ+←X2Σ+ )


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RbSr molecules…

Access to free RbSr molecules

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Dispersed Fluorescence SpectraFree 42Σ+ RbSr molecules


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X2Σ+ ground state: ωe ~ 42 cm-1 Theory[9,10]: 38-42 cm-1

[9]…Ẑuchowski et al. arXiv:1402.0702 (2014)[10]…Lackner et al. submitted manuscript (2014)

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Dispersed Fluorescence SpectraFree RbSr molecules

relaxation

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Dispersed Fluorescence SpectraFree RbSr molecules

shifted by-90 cm-1

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What’s coming next ?


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RbCa

Ca2

Helium droplet assisted “molecular engineering”

R2PI

LIF

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SummaryRecipe for the investigation of RbSr

Helium droplet assisted preparation of RbSr molecules

Covering large spectral ranges (11600 – 23000 cm-1) with R2PI spectroscopy

Preparing free RbSr molecules – DF spectroscopy

New perspectives for the formation of tailored molecules and ultracold molecular physics


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Thank you !


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Günter Krois

Johann V. Pototschnig

Wolfgang E. Ernst

Thomas Buchsteiner

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LIF vs. R2PI and Fragmentation

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4²Σ+ Fit and Sr2 background correction

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Dispersed Fluorescence Spectroscopy – Sr2

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(3)2Π1/2,3/2←(1)2Σ+ Transition

SO splitting ~13.5 cm-1

resolved on the droplet!

Broadened, asymmetric peaks due to the simultaneous excitation of the molecule and vibrations of the droplet (phonons)

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Isotope-shift: (3)2Π1/2,3/2←(1)2Σ+ Transition

Isotope-shift

Free molecule[4]

8.2 cm-1

17.4 cm-1

28.2 cm-1

[4] Russon et al., J. Chem. Phys., 138, 194307 (2013)

9 cm-1

18 cm-1 31 cm-1

LiCa on HeN

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