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  Januar 13 Name und OE, Eingabe über > Kopf- und Fußzeile

Helium droplets He N Thursday, Florian Lackner 2 Preparation and surface deposition of tailored clusters [4,5] Superfluidity from a microscopic perspective [1,4] Exotic Rydberg- atoms [2,3] Tailored molecules [6,7] [1]…Science 297, (2002) [2]…Phys. Rev. Lett. 106, (2011) [3]…Mol. Phys. 111, (2013) [4]…Phys. Rev. Lett. 108, (2012) [5]…J. Phys. Chem. 138, (2013) [6]…Science 273, (1996) [7]…J. Phys. Chem. A 117, (2013)

Thursday, Florian Lackner 3 Helium droplet assisted preparation of… Molecules [1,2,3] 0.1 nm 1 nm10 nm 100 nm Clusters Nanowires [1]…Science 273, (1996) [2]…Phys. Rev. Lett. 100, , (2008) [3]…J. Phys. Chem. A 117, (2013) Volk et al. J. Phys. Chem. 138, (2013) Thaler et al., submitted manuscript (2014)

RbSr molecules X 2 Σ + ground state: electric and magnetic dipole moment Thursday, Florian Lackner 4 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]… Ẑ uchowski et al. arXiv: (2014) [10]…Phys. Rev. Lett. 105, (2010) [11]…Phys. Rev. A 88, (2013) [12]…Phys. Rev. A 82, (2010) [13]…Lackner et al. submitted manuscript (2014) [8]…Phys. Rev. A 88, (2013)

Production of RbSr Molecules on He N Thursday, Florian Lackner 5 He N Pickup Rb Sr Source conditions: 15 K / 60 bar d ~ 8 nm

Spectroscopic Methods Thursday, Florian Lackner 6 Resonant two-photon ionization (R2PI) spectroscopy Laser induced fluorescence (LIF) spectroscopy Dispersed fluorescence (DF) spectroscopy

Thursday, Florian Lackner 7 RbSr on He N Time-of-flight mass spectra MonomersDimers and RbSr mass [amu] ion signal [arb. u.] Krois et al. in preparation

RbSr Potential Energy Curves MRCI calculations Thursday, Florian Lackner 8 For details see: talk FC07 Friday 10:07 AM Johann Pototschnig X2Σ+X2Σ+ RbSr-He N : only X 2 Σ + (ν" = 0) is populated (0.37 K) Lackner et al. submitted manuscript (2014)

RbSr-He N Excitation Spectrum Theory vs. experiment Thursday, Florian Lackner 9 R2PI spectroscopy Lackner et al. submitted manuscript (2014)

4 2 Σ + state: T e = 14006(4) cm -1 ω e = 86(3) cm -1 ω e x e = 1.2(0.7) cm Σ + ←X 2 Σ + Transition Vibrationally resolved Thursday, Florian Lackner 10 R2PI LIF Information on free RbSr molecules Insight into RbSr-He N Krois et al. in preparation

…desorb from the droplet upon laser excitation (4 2 Σ + ←X 2 Σ + ) Thursday, Florian Lackner 11 RbSr molecules… Access to free RbSr molecules

Dispersed Fluorescence Spectra Free 4 2 Σ + RbSr molecules Thursday, Florian Lackner 12 X 2 Σ + ground state: ω e ~ 42 cm -1 Theory [9,10] : cm -1 [9]… Ẑ uchowski et al. arXiv: (2014) [10]…Lackner et al. submitted manuscript (2014)

Thursday, Florian Lackner 13 Dispersed Fluorescence Spectra Free RbSr molecules relaxation

Thursday, Florian Lackner 14 Dispersed Fluorescence Spectra Free RbSr molecules shifted by -90 cm -1

What’s coming next ? Thursday, Florian Lackner 15 RbCa Ca 2 Helium droplet assisted “molecular engineering” R2PI LIF

Summary Recipe for the investigation of RbSr Helium droplet assisted preparation of RbSr molecules Covering large spectral ranges (11600 – cm -1 ) with R2PI spectroscopy Preparing free RbSr molecules – DF spectroscopy New perspectives for the formation of tailored molecules and ultracold molecular physics Thursday, Florian Lackner 16

Thursday, Florian Lackner 17 Recipe for RbSr 1g rubidium 1g strontium Beam of helium droplets Ingredience: Directions: Utilize R2PI spectroscopy to cover large spectral ranges (11600 – cm -1 ) and spice it with quantum chemical calculations Prepare free RbSr upon laser excitation, investigate them with DF spectroscopy At the end you get new perspectives for the formation of tailored molecules and ultracold molecular physics

Thank you ! Thursday, Florian Lackner 18 Günter Krois Johann V. Pototschnig Wolfgang E. Ernst Thomas Buchsteiner

Thursday, Florian Lackner 19 LIF vs. R2PI and Fragmentation

4²Σ + Fit and Sr 2 background correction

Dispersed Fluorescence Spectroscopy – Sr 2

(3) 2 Π 1/2,3/2 ←(1) 2 Σ + Transition SO splitting ~13.5 cm -1 resolved on the droplet! 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)

Isotope-shift: (3) 2 Π 1/2,3/2 ←(1) 2 Σ + Transition Isotope-shift Free molecule [4] 8.2 cm cm cm -1 [4] Russon et al., J. Chem. Phys., 138, (2013) 9 cm cm cm -1 LiCa on He N

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