1. Microsolvation studies in Helium nanodroplets: A status report
RUHR UNIVERSITY BOCHUM
Department Chemistry and Biochemistry
Physical Chemistry II
Microsolvation studies in Helium nanodroplets: A status report
Gerhard Schwaab, Matin Kaufmann, Daniel Leicht, Raffael Schwan,
Theo Fischer, Devendra Mani, Martina Havenith

2. Water 26°C
Bertie & Lan, Appl. Spectr. 50, 147,1996

3. HCl(aq): IR fingerprint region (ATR)
1.0M HCl/HBr
water
Kim et al., (2002). J.Chem.Phys.116, 737

4. HCl(aq): THz/FIR fingerprint
Eigen Complex
Decka, Schwaab, Havenith, (2015). PCCP17, 11898

5. Microsolvation in He nanodroplets
Challenges:
Fixed temperature
Non-equilibrium structures stabilized
Broad droplet size distribution
Advantages:
Weak He dopant interaction
Superfluid matrix
0.37 K: Few states populated
Ultracold aggregation
Non-equilibrium structures stabilized
Matrix assisted reactions

6. Experimental Setup: HENDI
Expansion
Pick-up
Excitation
QMS
Size selective detection of neutral species (0.37 K)

7. HCl water clusters: Experimental 1
Farnik et al., (2003). J.Chem.Phys.118, 10120

8. HCl water clusters: Experimental 2
Letzner et al, (2013). J.Chem.Phys.139,
Flynn et al., (2010). J.Phys.Chem.Lett.1, 2233

9. HCl water clusters: Theory
Lin & Paesani, (2015). J.Phys.Chem. A, 119, 4450
Sym.
Mancini & Bowman. (2015) PCCP, 17, 6222
Strong anharmonicity
Zero point delocalization
Asym.

10. Requirement: Extended Spectral Coverage
Microsolvation
Requirement: Extended Spectral Coverage

11. Extension 1: Quantum Cascade Lasers
Daylight solutions

12. Small water clusters in the bending region

13. Extension 2: FELIX Facility Nijmegen

14. First results: small water clusters

15. Summary
Microsolvation including ion formation is challenging:
Quantum Character of Proton
Solution: Extended frequency coverage
QCL: water bending mode
FELIX: libration band small water clusters
Outlook:
Microsolvation of neutral species
Ionisation reactions

16. Acknowledgements T. Fischer R. Schwan M. Kaufmann D. Mani D. Leicht
K. Hanke
M. Havenith
Photofragmentation Mass Spectrometry