Recent Publications

Recently Published Papers and Submitted Manuscripts

• Redshift or adduct stabilization - a computational study of hydrogen bonding in adducts of protonated carboxylic acids.
  Solveig Gaarn Olesen and Steen Hammerum,
  Europ. J. Mass Spectrom., 15, 239-48 (2009)

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• Reduction of 2-chloro-N-phenylpropanamide and 2-methyl-N-phenylaziridine with lithium aluminium hydride.
  Mie Højer Vilhelmsen, Lars Frøsig Østergaard, Mogens Brøndsted Nielsen and Steen Hammerum,
  Org. Biomol. Chem., 6, 1773-78 (2008)

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• The proton affinities of saturated and unsaturated heterocyclic molecules.
  Samira Kabli, Eric S. E. van Beelen, Steen Ingemann, Lars Henriksen and Steen Hammerum,
  Int. J. Mass Spectrom., 249, 370-78 (2006)

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• Intramolecular hydrogen bonding and hydrogen atom abstraction in gas-phase aliphatic amine radical cations.
  Steen Hammerum and Christian B. Nielsen,
  J. Phys. Chem. A, 109, 12046-53 (2005)

• Competing Simple Cleavage Reactions: The Elimination of Alkyl Radicals from Amine Radical Cations.
  Steen Hammerum, Kion Norrman, Theis I. Sølling, Peter E. Andersen, Lars Bo Jensen, and Tore Vulpius,
  J. Am. Chem. Soc., 127, 6466-6475 (2005)

• Isotope Effects on the Unimolecular Dissociation of Ionized 3-Methyl-2-butanol: Reactions via a Long-Lived C-H-C Hydrogen-Bridged Ion-Neutral Complex.
  Steen Hammerum, Lars Bo Jensen and Malene Mohr,
  J. Phys. Chem. A, 109, 3159-3165 (2005)

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• The Unimolecular Reactions of Ionized Acetamides.
  Lars Bo Jensen and Steen Hammerum,
  Europ. J. Mass Spectrom., 10, 783-90 (2004)

• The Formation and Heats of Formation of Simple alpha-Distonic Ions.
  Lars Bo Jensen and Steen Hammerum,
  Europ. J. Mass Spectrom., 10, 775-82 (2004)

• Experimental and Theoretical Evaluation of the Proton Affinities of Furan, Methylphenols and Related Anisoles.
  Eric S. E. van Beelen, Tehila A. Koblenz, Steen Ingemann and Steen Hammerum,
  J. Phys. Chem. A, 108, 2787 (2004)

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• Acyclic, Achiral Enamide Nucleoside Analogues. The Importance of the C=C Bond in the Analogue for its Ability to Mimic Natural Nucleosides.
  Asger B. Petersen, Michael Å. Petersen, Ulla Henriksen, Steen Hammerum and Otto Dahl,
  Org. Biomol. Chem., 1, 3293-96 (2003)

• Sproget som Redskab. K.A. Jensens Bidrag til Dansk Kemisk Nomenklatur og Terminologi.
  (Using Language as a Tool. K. A. Jensen's Contributions to Danish Chemical Nomenclature and Terminology.)
  Steen Hammerum,
  in K. A. Jensen - en Dansk Kemiker, red Carl Th. Pedersen, Dansk Selskab for Historisk Kemi, København 2003; pp 17-27; ISBN 87-89535-24-3

• Identification of Oxygenated Ions in Premixed Flames of Dimethyl Ether and Oxygen.
  Lars Frøsig-Østergaard, Helge Egsgaard and Steen Hammerum,
  Phys. Chem. Chem. Phys., 5, 3126 (2003)

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• Protonation of Fluorophenols and Fluoroanisoles in the Gas Phase: Experiments and Theory.
  Bogdan Bogdanovich, Dennis van Duijn, Steen Ingemann and Steen Hammerum,
  Phys. Chem. Chem. Phys., 4, 2904 (2002)

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• The retro-ene Reaction of Gaseous Immonium Ions Revisited.
  Theis I. Sølling and Steen Hammerum,
  J. Chem. Soc., Perkin Trans. 2, 2001, 2324

• The Methylene Chloride Radical Cation and its Distonic Isomers in the Gas Phase.
  Allan C. Petersen and Steen Hammerum,
  Int. J. Mass Spectrom., 210, 403 (2001)

• Gas-Phase Synthesis of Difluorotetrakis(alkylamine)chromium(III) Complexes and the Influence of Steric Effects.
  Steen B. Nielsen and Gustav Bojesen,
  Submitted for publication

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• The rearrangement and simple cleavage reactions of metastable octanamine radical cations.
  Steen Hammerum and Tina Henriksen,
  Int. J. Mass Spectrom., 199, 79 (2000)

• The 1,2-migration of NH₃ in protonated beta-aminoalkyl radicals.
  Steen Hammerum,
  Int. J. Mass Spectrom., 199, 71 (2000)

• Probing the Lowest Coordination Number of Dianionic Platinum Cyanide Complexes in the Gas Phase: Dynamics of the Charge Dissociation Process.
  Gustav Bojesen, Preben Hvelplund, Thomas J. D. Jørgensen and Steen B. Nielsen,
  J. Chem. Phys., 113, 6608 (2000)

• Methyl loss from conventional and distonic isomers of C₃H₇N^.+
  Steen Hammerum, Jens Henriksen, Tina Henriksen and Theis I. Sølling,
  Int. J. Mass Spectrom., 195, 459 (2000)

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• Heats of formation and proton affinities by the G3 method.
  Steen Hammerum,
  Chem. Phys. Lett., 300, 529 (1999)

• Analysis of Tetracyclines in Raw Urine by Column Switching High Performance Liquid Chromatography and Tandem Mass Spectrometry.
  Allan Weimann and Gustav Bojesen,
  J. Chromatogr. B, 721, 47 (1999)

• Collision-Induced Dissociation of Noncovalent Complexes between Vancomycin Antibiotics and Peptide Ligand Stereoisomers: Evidence for Molecular Recognition in the Gas Phase.
  Thomas J. D. Jørgensen, D. Delforge, J. Remacle, Gustav Bojesen and Peter Roepstorff,
  Int. J. Mass Spectrom., 188 63 (1999)

• The proton affinities of imines and the heats of formation of immonium ions investigated with composite ab initio methods.
  Steen Hammerum and Theis I. Sølling,
  J. Am. Chem. Soc., 121, 6002 (1999)

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• Heats of formation of imine and enamine radical cations and the corresponding neutral molecules.
  Jens Henriksen and Steen Hammerum,
  Int. J. Mass Spectrom. Ion Processes, 179, 301 (1998)

• The Gas-Phase Reactivity of Coordinatively Unsaturated Transition Metal Complex Ions Towards Molecular Oxygen.
  Henrik Molina-Svendsen, Christine J. McKenzie and Gustav Bojesen,
  Inorganic Chemistry, 37, 1981 (1998)

• The Proton Affinities of Seven MALDI-Matrices Correlated with the Formation of Multiply Charged Ions.
  Thomas J. D. Jørgensen, Gustav Bojesen and H. Rahbek-Nielsen,
  Europ. Mass Spectrom., 4, 39 (1998)

• Ligand and H/D Exchange of Mn(H₂O)₆²⁺ and [Cu(H₂O)₅-H]⁺ in the Gas Phase
  Steen B. Nielsen and Gustav Bojesen,
  Chem. Commun., 1998, 613

• Analysis of Tetracycline, Oxytetracycline and Chlorotetracycline in Plasma Extracts by Electrospray Tandem Mass Spectrometry and by Liquid Chromatography.
  Allan Weimann, Gustav Bojesen and P. Nielsen,
  Analytical Letters, 31, 2053 (1998)

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• Isomerization and Fragmentation of Metastable Secondary Amine Radical Cations.
  Allan C. Petersen and Steen Hammerum,
  Acta Chem. Scand., 51, 1045 (1997)

• Heats of Formation of Gas-Phase Ions Calculated by Composite Ab Initio Procedures.
  Steen Hammerum,
  Int. J. Mass Spectrom. Ion Processes, 165, 63 (1997)

• The Order of Lithium Ion Affinities for the twenty Common alpha-Amino Acids. Calculation of Energy Well-depth of Ion-bound Dimers
  Ulla N. Andersen and Gustav Bojesen,
  J. Chem. Soc. Perkin 2, 1997, 323

• On the Release of Translational Energy when Stable Intermediate Ion-Neutral Complexes Dissociate.
  Steen Hammerum, Malene Mohr Hansen and Henri E. Audier,
  Int. J. Mass Spectrom. Ion Processes, 160, 183 (1997)

• The Expulsion of Alkyl Radicals from the Methylammoniomethyl Radical Cation and Related Distonic Ions.
  Steen Hammerum, Allan C. Petersen, Theis I. Sølling, Tore Vulpius and Herman Zappey,
  J. Chem. Soc. Perkin 2, 1997, 391

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• Anvendelse af FIA/MS/MS og LC/MS/MS til restkoncentrationsbestemmelser.
  K. Sonne, C.T. Pedersen and Gustav Bojesen,
  Dansk Kemi, 1996, 10, 24

• Deprotonation of alpha-distonic Ions; Proton Affinities of the alpha-Radicals.
  Henri E. Audier, Jacques Fossey, Philippe Mourgues, Danielle Leblanc and Steen Hammerum,
  Int. J. Mass Spectrom. Ion Processes, 157, 275 (1996)

• Formation of Proton Bound Dimers as the Driving Force for Alkyl Radical Loss in the Gas-Phase Reactions of Radical Cations.
  Henri E. Audier, Jacques Fossey, Philippe Mourgues, Terry B. McMahon and Steen Hammerum,
  J. Phys. Chem., 100, 18380 (1996)

• Measurements of the Kinetic Energy Released in Decompositions of Proton-bound Dimers of Primary Amines
  Kirsten H. Lund and Gustav Bojesen
  Int. J. Mass Spectrom. Ion Processes, 156, 203 (1996)

• Gas Phase Ion-molecule Reactions of Doubly-charged Clusters of Fe²⁺ or Mn²⁺ and Methanol with Ammonia
  Ulla N. Andersen and Gustav Bojesen
  Int. J. Mass Spectrom. Ion Processes, 153, 1 (1996)

• Anthocyanins in Chilean Species of Alstroemeria
  Rikke Nørbæk, Lars P. Christensen, Gustav Bojesen and Kirsten Brandt
  Phytochemistry, 42, 97 (1996)

• Generation of Covalent and Electrostatic Complexes in Association Reactions of t-Butyl Cation with Small Organics.
  Kim Norrman and Terry B. McMahon,
  J. Am. Chem. Soc., 118, 2449 (1996)

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• On the Relative Heats of Formation of Protonated Acetone and its Isomers - a G2(MP2) and CBS-Q Study.
  Peter E. Andersen and Steen Hammerum,
  Europ. Mass Spectrom., 1, 499 (1995)

• A Kinetic Analysis of Collision Experiments in Triple Quadrupole Instruments; Validation of the Kinetic Method
  Steen B. Nielsen and Gustav Bojesen
  Europ. Mass Spectrom., 1, 423 (1995)

• Loss of H₂ from CH₃NH₃⁺, CH₃OH₂⁺ and CH₃FH⁺. Reaction Mechanisms and Dynamics from Observation of Metastable Ion Fragmentations and ab initio Calculations.
  Tore Vulpius, Elisabeth L. Øiestad, Åse Marit L. Øiestad, Haakon Skaane, Kenneth Ruud, Trygve Helgaker and Einar Uggerud,
  Europ. Mass Spectrom., 1, 121 (1995)

• Analysis of Multiply Charged Oxo-bridged Complexes by Electrospray Ionization Mass Spectrometry
  Ulla N. Andersen, Christine J. McKenzie and Gustav Bojesen
  Inorg. Chem., 34, 1435 (1995)

• Evidence for the Formation of Transient CH₄@C₆₀^+. following High-Energy Collisions between C₆₀^+. Radical Cations and Methane.
  Helen J. Cooper, R. T. Gallagher, P. F. Greenwood, Tore Vulpius and Peter J. Derrick,
  J. Chem. Soc. Chem. Commun., 1995, 1459

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• The Unimolecular Chemistry of Protonated Formamide. Mass Spectrometry and Ab Initio Quantum Chemical Calculations.
  H.-Y. Lin, Douglas P. Ridge, Tore Vulpius and Einar Uggerud,
  J. Am. Chem.Soc., 116, 2996 (1994)

• Catalysed Isomerization of Simple Radical Cations in the Gas Phase.
  Henri E. Audier, Danielle Leblanc, Philippe Mourgues, Terry B. McMahon and Steen Hammerum,
  J. Chem. Soc. Chem. Commun., 1994, 2329

• The Methoxymethyl Cation Revisited: Experimental and Theoretical Study.
  Henri E. Audier, Guy Bouchoux, Terry B. McMahon, Arielle Milliet and Tore Vulpius,
  Org. Mass Spectrom., 29, 176 (1994)

• A Regiospecific Cycloaddition: Successive Reactions of ^.CH₂CH₂OH₂⁺ with CH₂O.
  Philippe Mourgues, Henri E. Audier and Steen Hammerum,
  Rapid Comm. Mass Spectrom., 8, 53 (1994)

• On the Proton Affinity of Some alpha-Amino Acids and the Theory of the Kinetic Method
  Gustav Bojesen and Torben Breindahl
  J. Chem. Soc., Perkin Trans. 2 , 1994, 1029

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• On the Sodium and Lithium Ion Affinity of Some alpha-Amino Acids
  Gustav Bojesen, Torben Breindahl, and Ulla N. Andersen
  Org. Mass Spectrom., 28, 1448 (1993)

• Bimolecular Ionic Alkene Displacement Reactions in the Gas Phase.
  Henri E. Audier, Philippe Mourgues, Danielle Leblanc and Steen Hammerum,
  Compt. Rends. Acad. Sci. II, 317, 27 (1993)

• Bimolecular Reactions of Distonic Ions: Proton Transfer and Hydrogen Atom Abstraction with ^.CH₂OH₂⁺.
  Philippe Mourgues, Henri E. Audier, Danielle Leblanc and Steen Hammerum,
  Org. Mass Spectrom., 28, 1098 (1993)

• Mechanism, Energetics, Kinetics, and Dynamics of the Reaction C₂H₆^+. -> C₂H₄^+. + H₂.
  Svein M. Bråten, Trygve Helgaker, Einar Uggerud and Tore Vulpius,
  Org. Mass Spectrom., 28, 1262 (1993)

• Addition of Alkenes to Phenyl Substituted Enol Radical Cations.
  Philippe Mourgues, Jean-Pierre Denhez, Henri E. Audier and Steen Hammerum,
  Org. Mass Spectrom., 28, 193 (1993)

• Bimodal Internal Energy Distribution as a Consequence of Cul-de-sac Isomerization Reactions.
  Steen Hammerum, Tore Vulpius and Henri E. Audier,
  Org. Mass Spectrom., 27, 369 (1992)

• Distinction Between C₃H₆^+. Isomers: Reactions of Cyclopropane and Propene Radical Cations with Water and Methanol at Low Pressure.
  Philippe Mourgues, Danielle Leblanc, Henri E. Audier and Steen Hammerum,
  Int. J. Mass Spectrom. Ion Processes, 113, 105 (1992)

Reviews

• Distonic Radical Cations in Gaseous and Condensed Phase.
  Steen Hammerum,
  Mass Spectrometry Reviews, 7, 123 (1988)

• Isomers and Isomerization of Molecular Ions: the Formation of Stable Ion-Neutral Complexes During Unimolecular Dissociation.
  Steen Hammerum,
  in Fundamentals of Gas-Phase Ion Chemistry, ed. K.R. Jennings; Kluwer, Dordrecht 1991; p 379

Notes (in Danish)

• Terminologi indenfor massespektrometrien.
• Litteraturhenvisninger og noter i rapporter og manuskripter.

• Vejledning i brug af Gaussian programpakken.
• Gaussian-beregninger med G3, CBS-Q og andre sammensatte metoder
• Termokemiske beregninger med Gaussian

• Praktiske anvisninger ved reduktion med lithiumaluminiumhydrid.
• Praktiske anvisninger ved arbejde med Grignardreagenser.