1. 2017:

  2. Bullet S. Schlemmer, S. Willitsch and T. Steimle,
    "Introduction to the special issue on molecular spectroscopy in traps"
    J. Mol. Spetrosc. 118, (2017), 1

  3. BulletI. Rouse and S. Willitsch,
    "Superstatistical energy distributions of an ion in an ultracold buffer gas"
    Phys. Rev. Lett. 118, 14301 (2017)

  4. BulletU. Rivero, M. Meuwly and S. Willitsch,
    "A Computational Study of the Diels-Alder Reactions Between 2,3-Dibromo-1,3-Butadiene and Maleic Anhydride"
    Chem. Phys. Lett., dx.doi.org/10.1016/j.cplett.2017.03.063

  5. BulletD. Zhang and S. Willitsch,
    "Cold ion chemistry"
    "Low Energy and Low Temperature Molecular Scattering", RSC Publishing, in press  (arXiv:1703.07133)

  6. BulletS. Willitsch,
    "Chemistry with controlled ions"
    in Adv. Chem. Phys. vol. 162, in press

  7. BulletO. Dulieu and S. Willitsch,
    "Ion Coulomb crystals: From quantum technology to chemistry close to the absolute zero point "
    Europhysics News 48(2) (2017), 17

  8. BulletD. Rösch und S. Willitsch,
    "Spektroskopie und Chemie mit kalten Ionen"
    Nachrichten aus der Chemie, 65 (2017), 326

  9. BulletA. Mokhberi, R. Schmeid and S. Willitsch,                                                                    
    "Optimised surface-electrode ion-trap junctions for experiments with cold molecular ions"
    New J. Phys., 19 (2017), 043023 (arXiv:1701.06408)

  10. 2016:


  1. Bullet P. Eberle, A. D. Dörfler, C. von Planta, K. Ravi and S. Willitsch,                                                                     "A dynamic ion-atom hybrid trap for high-resolution cold-collision studies 
    ChemPhysChem, 173769-3775 (2016)

  2. BulletDaniel Rösch, Hong Gao, Ardita Kilaj and Stefan Willitsch,                                                                     "Design and characterization of a linear quadrupole ion trap for high-resolution Coulomb-crystal time-of-flight mass spectrometry
    EPJ Tech. Instr. 3:5 (2016)

  3. BulletM. Germann and S. Willitsch,
    "Fine- and hyperfine-structure effects in molecular photoionization: I. General theory and direct photoionization
    J. Chem. Phys. 145, 044314 (2016)

  4. BulletM. Germann and S. Willitsch,
    "Fine- and hyperfine-structure effects in molecular photoionization: II. Resonance-enhanced multiphoton ionization and hyperfine-selective generation of molecular cations”                                                              J. Chem. Phys. 145, 044315 (2016)

  5. BulletL. Ploenes, D. Haas, D. Zhang, S.  Y. T. van de Meerakker and S. Willitsch,
    "Cold and intense OH radical beam sources”
    Rev. Sci. Instrum. 635, 053305 (2016)

  6. BulletM. Germann and S. Willitsch,
    "Line strengths for fine- and hyperfine-resolved electric-quadrupole rotation-vibration transitions in Hund’s case b molecules”
    Mol. Phys. 114, 769-773 (2016)


  7. 2015:


  1. BulletI. Rouse and S. Willitsch,
    "Superstatistical velocity distributions of cold trapped ions in molecular dynamics simulations"
    Phys. Rev. A 92, 053420 (2015) (arXiv 1510.03985)

  2. BulletP. Eberle, A.D. Dörfler, C. von Planta, R. Krishnamurthy, D. Haas, D. Zhang, S.Y. T. van de Meerakker and S. Willitsch,
    "Ion-Atom and Ion-Molecule Hybrid Systems: Ion-Neutral Chemistry at Ultralow Energies"
    J. Phys. Conf. Ser. 635, 012012 (2015)

  3. BulletS. Willitsch,
    "Ion-atom hybrid systems"
    Proc. Int. Sch. Phys. Enrico Fermi 189, 255 (2015)

  4. BulletO. Dulieu and S. Willitsch,
    “Cristaux coulombiens: De la technologie quantique à la chimie proche du zéro absolu”
    Reflets Phys. 44-45, 91 (2015)

  5. BulletM. Germann, X. Tong and S. Willitsch,
    "Forbidden Vibrational Transitions in Cold Molecular Ions: Experimental Observation and Potential Applications"
    Chimia 69, 213 (2015)

  6. BulletA. Mokhberi and S. Willitsch,
    "Structural and energetic properties of molecular Coulomb crystals in a surface-electrode ion trap"
    New J. Phys. 17, 045008 (2015) invited for the Focus on New Frontiers of Cold Molecules Research


  7. 2014:

  8. BulletM. Germann, X. Tong and S. Willitsch,
    “Observation of electric-dipole-forbidden infrared transitions in cold molecular ions”
    Nature Phys. 10, 820 (2014) 

  9. BulletA. Mokhberi and S. Willitsch;
    "Sympathetic cooling of molecular ions in a surface-electrode ion trap”
    Phys. Rev. A 90, 023402 (2014) (arXiv:1404.4292 [physics.atom-ph])

  10. BulletD. Rösch, S. Willitsch, Y.-P. Chang, J. Küpper;
    "Chemical reactions of conformationally selected 3-aminophenol molecules in a beam with Coulomb-crystallized Ca+ ions”
    J. Chem. Phys. 140, 124202 (2014)


  1. 2013:

  2. BulletY.-P. Chang, K. Dlugolecki, J. Küpper, D. Rösch, D. Wild, S. Willitsch;
    "Specific Chemical Reactivities of Spatially Separated 3-Aminophenol Conformers with Cold Ca+ Ions"
    Science 342, 98 (2013)
    Corresponding perspective by Michael C. Heaven:
    “Turn the Molecule This Way for a Faster Reaction”
    Science 342, 46 (2013)

  3. BulletS. Willitsch;
    "Ultracold ménage a trois"
    Nature Phys. 9, 461 (2013)

  4. BulletFelix H. J. Hall, Pascal Eberle, Gregor Hegi, Maurice Raoult, Mireille Aymar, Olivier Dulieu, and Stefan Willitsch;
    "Ion-neutral chemistry at ultralow energies: Dynamics of reactive collisions between laser-cooled Ca+ ions and Rb atoms in an ion-atom hybrid trap",
    Mol. Phys. 111, 14-15, 2020-2032 (2013) (arXiv:1302.4682 [physics.atom-ph])

  5. BulletFelix H. J. Hall, Mireille Aymar, Maurice Raoult, Olivier Dulieu, and Stefan Willitsch;
    "Light-Assisted Cold Chemical Reactions of Barium Ions with Rubidium Atoms",
    Mol. Phys. 111, 12-13, 1683-1690 (2013) (arXiv:1301.0724 [physics.atom-ph])

  6. 2012:

  7. BulletFelix H. J. Hall and Stefan Willitsch;
    "Millikelvin Reactive Collisions between Sympathetically-Cooled Molecular Ions and Laser-Cooled Atoms in an Ion-Atom Hybrid Trap",
    Phys. Rev. Lett. 109 233202 (2012)

  8. BulletXin Tong, Tibor Nagy, Juvenal Yosa Reyes, Matthias Germann, Markus Meuwly, Stefan Willitsch;
    "State-selected ion-molecule reactions with Coulomb-crystallized molecular ions in traps",
    Chem. Phys. Lett. 547 1-8 (2012) (Frontiers and cover article)

  9. BulletJ. Mur-Petit, J. Perez-Rios, J. Campos-Martinez, M. I. Hernandez, S. Willitsch, and J. J. Garcia-Ripoll;
    "Towards a Molecular Ion Qubit",
    to appear in "Advances in Atom and Molecule Machines”, Vol. 2, Springer 2012

  10. BulletJordi Mur-Petit, Juan Jose Garcıa-Ripoll, Jesus Perez-Rios, Jose Campos-Martinez, Marta I. Hernandez, and Stefan Willitsch;
    “Temperature-independent quantum logic for molecular spectroscopy”,
    Phys. Rev. A 85, 022308 (2012)

  11. BulletStefan Willitsch;
    “Coulomb-crystallised molecular ions in traps: methods, applications, prospects”,
    Int. Rev. Phys. Chem. 31 175-199 (2012)

  12. 2011:

  13. BulletOlivier Dulieu, Roman Krems, Matthias Weidemüller and Stefan Willitsch,
    “Physics and Chemistry of Cold Molecules”,
    Phys. Chem. Chem. Phys., 2011, 13, 18703

  14. BulletFelix H.J. Hall, Mireille Aymar, Nadia Bouloufa, Olivier Dulieu, and Stefan Willitsch,
    “Light-assisted ion-neutral reactive processes in the cold regime: radiative molecule formation vs. charge exchange”,
    Phys. Rev. Lett. 107, (2011) 243202

  15. BulletI.M. Georgescu and S. Willitsch,
    "Theoretical characterization of laser- and sympathetically-cooled ions in surface-electrode ion traps ",
    Phys. Chem. Chem. Phys., 2011, 13, 18852

  16. BulletX. Tong, D. Wild and S. Willitsch,
    “Collisional and radiative effects in the state-selective preparation of translationally cold molecular ions in ion traps”,
    Phys. Rev. A 83 (2011), 023415

  17. BulletS. Willitsch,
    “Experimental methods in cation spectroscopy”,
    p. 1691 in Handbook of High-Resolution Spectroscopies, ed. M. Quack and F. Merkt, Wiley 2011

  18. BulletF. Merkt, S. Willitsch and U. Hollenstein,
    “High-resolution photoelectron spectroscopy”,
    p. 1617 in Handbook of High-Resolution Spectroscopies, ed. M. Quack and F. Merkt, Wiley 2011

  19. 2010:

  20. BulletJ.P. Maier and S. Willitsch,
    “Spectroscopy and Chemical Dynamics”,
    Chimia 64 (2010), 855

  21. BulletS. Willitsch,
    "Ultrakalte Chemie - Nahe am Nullpunkt",
    Nachrichten aus der Chemie 58 (2010), 872

  22. BulletX. Tong, A. H. Winney and S. Willitsch,
    "Sympathetic cooling of rotationally and vibrationally state-selected molecular ions produced by threshold photoionization",
    Phys. Rev. Lett. 105 (2010), 143001

  23. BulletS. Willitsch,
    "Very cool molecular ions" (News & Views Feature),
    Nature Physics 6 (2010), 240

  24. 2009:

  25. BulletM.T. Bell, A.D. Gingell, J. Oldham, T. P. Softley and S. Willitsch,
    “Ion-molecule chemistry at very low temperatures: cold chemical reactions between Coulomb-crystallised ions and velocity-selected neutral molecules”,
    Faraday Discuss. 142 (2009), 73

  26. BulletS. Willitsch,
    “Molecules and Ions at Very Low Temperatures”,
    Chimia 63 (2009), 54

  27. 2008:

  28. BulletS. Willitsch, M. Bell, A. Gingell and T.P. Softley,
    "Chemical applications of laser- and sympathetically cooled ions in ion traps",
    Phys. Chem. Chem. Phys., 10 (2008), 7200

  29. BulletS. Willitsch, M. Bell, A. Gingell, S. R. Procter and T. P. Softley,
    "Cold reactive collisions between laser-cooled ions and velocity-selected neutral molecules",
    Phys. Rev. Lett. 100 (2008), 043203

  30. 2007:

  31. BulletS.J. Matthews, S. Willitsch and T.P. Softley,
    ''A fully quantum-state selected velocity-map imaging study of the near-threshold photodissociation of NO2'',
    Phys. Chem. Chem. Phys. 9 (2007), 5656

  32. BulletU. Hollenstein, F. Merkt, L. Meyer, R. Seiler, T.P. Softley and S. Willitsch,
    ''Rovibronic photoionization dynamics of ammonia isotopomers'',
    Mol. Phys. 105 (2007), 1711

  33. 2006:

  34. BulletS. Willitsch, Ch. Jungen and F. Merkt,
    ''Bending energy level structure and quasilinearity of the X+ 3B1 ground electronic state of NH2+'',
    J. Chem. Phys., 124 (2006), 204312

  35. BulletS. Willitsch, F. Merkt, M. Kallay and J. Gauss,
    ''Thermochemical properties of open-shell systems: Experimental and high-level ab initio results for NH2 and NH2+”,
    Mol. Phys., 104 (2006), 1457

  36. 2005:

  37. BulletS. Willitsch and F. Merkt,
    ''Rovibronic photoionization dynamics of asymmetric top molecules'',
    Int. J. Mass Spectrom., 245 (2005), 14

  38. BulletS. Willitsch, F. Innocenti, J. M. Dyke and F. Merkt,
    ''High-resolution pulsed-field-ionization zero-kinetic-energy photoelectron spectroscopic study of the two lowest electronic states of the ozone cation O3+'',
    J. Chem. Phys. 122 (2005), 024311

  39. 2004:

  40. BulletS. Willitsch, J.M. Dyke and F. Merkt,
    ''First rotationally resolved study of the a 1A1 ground electronic state of singlet NH2+'',
    Mol. Phys. 102 (2004), 1543

  41. BulletS. Willitsch, A.F. Wüest und F. Merkt,
    ''High-Resolution Photoelectron Spectroscopy and Ab-Initio Quantum Chemistry'',
    Chimia 58 (2004), 281

  42. BulletS. Willitsch, U. Hollenstein and F. Merkt,
    ''Ionization from a double bond: Rovibronic photoionization dynamics of ethylene, large amplitude torsional motion and vibronic coupling in the ground state of C2H4+'',
    J. Chem. Phys. 120 (2004), 1761

  43. 2003:

  44. BulletS. Willitsch, J. M. Dyke and F. Merkt,
    ''Generation and High-Resolution Photoelectron Spectroscopy of Small Organic Radicals in Cold Supersonic Expansions'',
    Helv. Chim. Acta 86 (2003), 1152

  45. BulletS. Willitsch and F. Merkt,
    ''Characterization of the X 2A1 (0,0,0) ground vibronic state of CH2+ by pulsed-field-ionization zero-kinetic-energy photoelectron spectroscopy'',
    J. Chem. Phys. 118 (2003), 2235

  46. 2002:

  47. BulletS. Willitsch, L.L. Imbach and F. Merkt,
    ''The ionization energy of methylene (CH2) from a rotationally resolved photoelectron spectrum and its thermochemical implications'',
    J. Chem. Phys. 117 (2002), 1939

  48. BulletS. Willitsch, A. Haldi and F. Merkt,
    ''Rovibrational energy level structure of the X 2B1 ground electronic state of CH2CO+ and CD2CO+'',
    Chem. Phys. Lett. 353 (2002), 167

  49. BulletU. Hollenstein, R. Seiler, A. Osterwalder, M. Sommavilla, A. Wüest, P. Rupper, S. Willitsch, G.M. Greetham, B. Brupbacher-Gatehouse and F. Merkt,
    ''High-Resolution Vacuum Ultraviolet Photoelectron Spectroscopy'',
    Chimia 55 (2001), 759

  50. 2001:

  51. BulletA. Osterwalder, S. Willitsch and F. Merkt,
    ''High-resolution pulsed field ionization study of high Rydberg states of benzene'',
    J. Mol. Struct. 599 (2001), 163

Publications