A. D. Dörfler, E. Yurtsever, P. Villarreal, T. González-Lezana, F. A. Gianturco and S. Willitsch,
”Rotational state-changing collisions between N2+ and Rb at low energies”

Phys. Rev. A 101 (2020), 012706 (arxiv 1910.12543)

Z. Meir, M. Sinhal, M. S. Safronova and S. Willitsch
"Combining experiments and relativistic theory for establishing accurate radiative quantities in atoms: the lifetime of the 2P3/2 state in 40Ca+"

Phys. Rev. A 101 (2020), 012509 (arXiv 1909.1051) (supporting data at 10.5281/zenodo.3532722)

M. Sinhal, Z. Meir, K. Najafian, G. Hegi and S. Willitsch,
"Quantum non-demolition state detection and spectroscopy of single trapped molecules"

Science 367 (2020), 1213 (arXiv 1910.11600) (supporting data at 10.5281/zenodo.3532942)

K. Najafian, Z. Meir, M. Sinhal and S. Willitsch,
"Identification of molecular quantum states using phase-sensitive forces"

arXiv 2004.05306 

A. Kilaj, H. Gao, D. Tahchieva, R. Ramakrishnan, D. Bachmann, D. Gillingham, O. A. von Lilienfeld, J. Küpper and S. Willitsch
"Quantum-chemistry-aided identification, synthesis and experimental validation of model systems for conformationally controlled reaction studies: Separation of the conformers of 2,3-dibromobuta-1,3-diene in the gas phase"

accepted by Phys. Chem. Chem. Phys. (arxiv 2004.09659)

P. Fountas, M. Poggio and S. Willitsch,
"Classical and quantum dynamics of a trapped ion coupled to a charged nanowire”

New J. Phys. 21 (2019), 013030

Z. Meir, G. Hegi, K. Najafian, M. Sinhal and S. Willitsch,
"State-selective coherent motional excitation as a new approach for the manipulation, spectroscopy and state-to-state chemistry of single molecular ions”

Faraday Discuss. 217 (2019), 561 (arxiv 1909.10292)

 F. A. Gianturco, A. D. Dörfler, S. Willitsch, E. Yurtsever, T. González-Lezana and P. Villarreal,
“N2+ (2Σ+g) and Rb(2S) in a hybrid trap: Modeling ion losses from radiative association paths"

Phys. Chem. Chem. Phys. 21 (2019), 8342

I. Rouse and S. Willitsch,
"The energy distribution of an ion in a radiofrequency trap interacting with a nonuniform neutral buffer gas"

Mol. Phys. 117 (2019), 3120 (arXiv 1811.1213)

D. Haas, C. von Planta, Th. Kierspel, D. Zhang and S. Willitsch
“Long-term trapping of Stark-decelerated molecules"

Commun. Phys. 2 (2019), 101 (arxiv 1904.00713)

U. Rivero, O. T. Unke, M. Meuwly and S. Willitsch,
"Reactive Atomistic Simulations of Diels-Alder Reactions: the Importance of Molecular Rotations"

J. Chem. Phys. 151 (2019), 104301 (arXiv 1906.07455) (supporting data at 10.5281/zenodo.3291502)

A. D. Dörfler, P. Eberle, D. Koner, M. Tomza, M. Meuwly and S. Willitsch,
"Long-range vs. short-range effects in cold molecular ion-neutral collisions: Charge exchange of Rb with N2+ and O2+"

Nat. Commun. 10 (2019), 5429 (arXiv 1906.12285)

Z. Meir, D. Zhang and S. Willitsch,
“Cold molecules: techniques and applications"

SPG Mitteilungen 55 (2018), 31

A. Kilaj, H. Gao, D. Rösch, U. Rivero, J. Küpper and S. Willitsch
"Observation of different reactivities of para- and ortho-water towards trapped diazenylium ions"

Nat. Commun. 9 (2018), 2096 (arXiv 1804.05925)

I. Rouse and S. Willitsch,

"Energy distributions of an ion in a radiofrequency trap immersed in a buffer gas under the influence of additional external forces"

Phys. Rev. A 97 (2018), 042712

 D. Haas, S. Scherb, D. Zhang and S. Willitsch,

"Optimizing the density of Stark decelerated radicals at low final velocities: a tutorial review"

EPJ Techn. Instrum. (2017), 4: 6

 S. Schlemmer, S. Willitsch and T. Steimle,
"Introduction to the special issue on molecular spectroscopy in traps"

J. Mol. Spetrosc. 118, (2017), 1 

 I. Rouse and S. Willitsch,
"Superstatistical energy distributions of an ion in an ultracold buffer gas"

Phys. Rev. Lett. 118 (2017), 143401

U. 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. 683 (2017), 598

S. Willitsch,
"Chemistry with controlled ions"

Adv. Chem. Phys. 162 (2017), 307

O. Dulieu and S. Willitsch,
"Ion Coulomb crystals: From quantum technology to chemistry close to the absolute zero point"

Europhysics News 48(2) (2017), 17

D. Rösch und S. Willitsch,
"Spektroskopie und Chemie mit kalten Ionen"

Nachrichten aus der Chemie, 65 (2017), 326

A. 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

 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, 17,  3769-3775 (2016)

 Daniel 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)

M. Germann and S. Willitsch,
"Fine- and hyperfine-structure effects in molecular photoionization: I. General theory and direct photoionization”

J. Chem. Phys. 145, 044314 (2016)

M. 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)

L. 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)

M. 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)

I. Rouse and S. Willitsch,
"Superstatistical velocity distributions of cold trapped ions in molecular dynamics simulations" 

Phys. Rev. A 92, 053420 (2015) arXiv 1510.03985

P. 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)

S. Willitsch,
"Ion-atom hybrid systems" 

Proc. Int. Sch. Phys. Enrico Fermi 189, 255 (2015)

O. Dulieu and S. Willitsch, 
“Cristaux coulombiens: De la technologie quantique à la chimie proche du zéro absolu”

Reflets Phys. 44-45, 91 (2015)

M. Germann, X. Tong and S. Willitsch,
"Forbidden Vibrational Transitions in Cold Molecular Ions: Experimental Observation and Potential Applications"

Chimia 69, 213 (2015)

A. 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

M. Germann, X. Tong and S. Willitsch,
“Observation of electric-dipole-forbidden infrared transitions in cold molecular ions”

Nature Phys. 10, 820 (2014)  

A. Mokhberi and S. Willitsch;
"Sympathetic cooling of molecular ions in a surface-electrode ion trap”

Phys. Rev. A 90, 023402 (2014) arXiv:1404.4292 

D. 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) 

Y.-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" 

Corresponding perspective by Michael C. Heaven: 
“Turn the Molecule This Way for a Faster Reaction”

Science 342, 98 (2013) Science 342, 46 (2013)

S. Willitsch;
"Ultracold ménage a trois"

Nature Phys. 9, 461 (2013)

Felix 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 

Felix 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 

Felix 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) 

Xin 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)

J. Mur-Petit, J. Perez-Rios, J. Campos-Martinez, M. I. Hernandez, S. Willitsch, and J. J. Garcia-Ripoll;
"Towards a Molecular Ion Qubit"

"Advances in Atom and Molecule Machines”, Vol. 2, Springer 2012

Jordi 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)

Stefan Willitsch;
“Coulomb-crystallised molecular ions in traps: methods, applications, prospects”

Int. Rev. Phys. Chem. 31 175-199 (2012) 

Olivier Dulieu, Roman Krems, Matthias Weidemüller and Stefan Willitsch,
“Physics and Chemistry of Cold Molecules”

Phys. Chem. Chem. Phys., 2011, 13, 18703

Felix 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 

I.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 

X. 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

F. 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

J.P. Maier and S. Willitsch,
“Spectroscopy and Chemical Dynamics”

Chimia 64 (2010), 855

S. Willitsch,
"Ultrakalte Chemie - Nahe am Nullpunkt"

Nachrichten aus der Chemie 58 (2010), 872

X. 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

S. Willitsch,
"Very cool molecular ions" (News & Views Feature),

Nature Physics 6 (2010), 240

M.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

S. Willitsch,
“Molecules and Ions at Very Low Temperatures”

Chimia 63 (2009), 54

S. 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

S. 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

S.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

U. Hollenstein, F. Merkt, L. Meyer, R. Seiler, T.P. Softley and S. Willitsch,
''Rovibronic photoionization dynamics of ammonia isotopomers''

Mol. Phys. 105 (2007), 1711

S. 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

S. 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

S. Willitsch and F. Merkt,
''Rovibronic photoionization dynamics of asymmetric top molecules''

Int. J. Mass Spectrom., 245 (2005), 14

S. 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

S. Willitsch, J.M. Dyke and F. Merkt,
''Rotationally resolved photoelectron spectrum of the lowest singlet electronic state of NH2 +and ND2 +: photoionization dynamics and rovibrational energy level structure of the ã+1A1 state''

Mol. Phys. 102 (2004), 1543

S. Willitsch, A.F. Wüest und F. Merkt,
''High-Resolution Photoelectron Spectroscopy and Ab-Initio Quantum Chemistry''

Chimia 58 (2004), 281

S. 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

S. 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

S. 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

S. 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

S. 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

U. 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

A. Osterwalder, S. Willitsch and F. Merkt,
''High-resolution pulsed field ionization study of high Rydberg states of benzene''

J. Mol. Struct. 599 (2001), 163