Rubidium on Helium Droplets: Analysis of an Exotic Rydberg Complex for n* < 20 and 0 ≤ l ≤ 3.

Rubidium atom Rydberg states perturbed by helium droplets of different sizes provide insight into the role of a nanosized dielectric on the Coulomb potential. The observation of droplet size-dependent shifts of excited states with respect to bare atom states is explained by a decreased quantum defect and a lowered ionization threshold. Within the scope of a Rydberg model, we demonstrate that quantum defects and ionization potentials are constant for each specific Rydberg series, which confirms the Rydberg character of excited Rubidium states on helium droplets. A set of six Rydberg series could be identified. Individual Rydberg states are observed with effective principal quantum numbers up to n* ≈ 19 and l ≤ 3, for which the expectation value of the electron orbital radius is about 10 times larger than the droplet radius.

[1]  M. Mudrich,et al.  Photoionization and imaging spectroscopy of rubidium atoms attached to helium nanodroplets. , 2011, Physical chemistry chemical physics : PCCP.

[2]  W. Ernst,et al.  Ionization Thresholds of Alkali Metal Atoms on Helium Droplets , 2011 .

[3]  W. Ernst,et al.  Spectroscopy of nS, nP, and nD Rydberg series of Cs atoms on helium nanodroplets. , 2011, Physical chemistry chemical physics : PCCP.

[4]  C. Callegari,et al.  Helium Droplets as Nanocryostats for Molecular Spectroscopy—from the Vacuum Ultraviolet to the Microwave Regime , 2011 .

[5]  C. Callegari,et al.  Spectroscopy on Rydberg states of sodium atoms on the surface of helium nanodroplets. , 2011, The journal of physical chemistry. A.

[6]  C. Callegari,et al.  Perturbation method to calculate the interaction potentials and electronic excitation spectra of atoms in He nanodroplets. , 2011, The journal of physical chemistry. A.

[7]  M. Drabbels,et al.  Unusual Rydberg system consisting of a positively charged helium nanodroplet with an orbiting electron. , 2011, Physical review letters.

[8]  C. Callegari,et al.  One- and two-photon spectroscopy of highly excited states of alkali-metal atoms on helium nanodroplets. , 2010, The Journal of chemical physics.

[9]  C. Callegari,et al.  Two-step excitation of Rb atoms on He nanodroplets , 2011 .

[10]  J. Shaffer,et al.  Observation of ultralong-range Rydberg molecules , 2009, Nature.

[11]  W. Ubachs,et al.  Observation of a Rydberg series in H+H-: a heavy Bohr atom. , 2008, Physical review letters.

[12]  C. Callegari,et al.  Electron spin pumping of Rb atoms on He nanodroplets via nondestructive optical excitation. , 2008, Physical review letters.

[13]  C. Callegari,et al.  High-spin alkali trimers on helium nanodroplets: spectral separation and analysis. , 2008, The Journal of chemical physics.

[14]  A. Hernando,et al.  Unraveling the absorption spectra of alkali metal atoms attached to helium nanodroplets. , 2007, The journal of physical chemistry. A.

[15]  C. Callegari,et al.  Optical spectroscopy of potassium-doped argon clusters. Experiments and quantum-chemistry calculations. , 2007, The journal of physical chemistry. A.

[16]  M. Pi,et al.  Squeezing a helium nanodroplet with a Rydberg electron. , 2007, The journal of physical chemistry. A.

[17]  J. Toennies,et al.  Superfluid Helium Droplets: A Uniquely Cold Nanomatrix for Molecules and Molecular Complexes , 2004 .

[18]  J. Toennies,et al.  Superfluid helium droplets: a uniquely cold nanomatrix for molecules and molecular complexes. , 2004, Angewandte Chemie.

[19]  W. Ernst,et al.  Rb–He exciplex formation on helium nanodroplets , 2001 .

[20]  R. Neuhauser,et al.  HYDROGENLIKE RYDBERG ELECTRONS ORBITING MOLECULAR CLUSTERS , 1998 .

[21]  G. Scoles,et al.  Spectroscopy of alkali atoms (Li, Na, K) attached to large helium clusters , 1996 .

[22]  Field,et al.  Core-penetrating Rydberg series of BaF: s~p~d~f supercomplexes. , 1994, Physical review letters.

[23]  T. Gallagher.  Rydberg Atoms: Frontmatter , 1994 .

[24]  A. Golov,et al.  A new type of excimer atom: electron + ionized helium cluster , 1993 .

[25]  Harris,et al.  Rydberg states and ionization potential of calcium monofluoride. , 1990, Physical review letters.

[26]  K. Niemax,et al.  Quantum Defects of the n2P1/2,3/2 Levels in 39K I and 85Rb I , 1983 .