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Spektroskopie, Photophysik und Photochemie von Molekülclustern in Überschallmolekularstrahlen

English title Spectroscopy, photophysics and photochemistry of molecular clusters in supersonic beams
Applicant Leutwyler Samuel
Number 132540
Funding scheme Project funding (Div. I-III)
Research institution Departement für Chemie und Biochemie Universität Bern
Institution of higher education University of Berne - BE
Main discipline Physical Chemistry
Start/End 01.10.2010 - 31.03.2014
Approved amount 621'851.00
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Keywords (14)

nucleobases; nucleobase dimers; hydrogen-bond; pi-stacking; molecular excitons; proton transfer; H-atom transfer; intermolecular interactions; laser spectroscopy; molecular beams; hydrogen bonding; exciton; proton wires; nucleic acid bases

Lay Summary (German)

Lead
Lay summary
Projekt A, B: Spektroskopie von Nukleobasen und Nukleobasen-DimerenDie einzelnen intermolekularen Kräfte, welche die Nukleinsäurebasen in der DNA zusammenhalten und deren dreidimensionale Struktur beeinflussen, sind noch nicht im Detail bekannt. Gründe dafür sind die Vielfalt der Wechselwirkungen (mehrere Wasserstoffbrücken pro Nukleobase, pi-Stapel-Wechselwirkungen, hydrophobe Wechselwirkungen), der Einfluss des Zucker-Phosphatrückgrats und die Einflüsse von Hydratwasser und Ionen. Ziel des Projekts ist die direkte, exakte Messung und Berechnung der Struktur, der Vibrations-Kraftkonstanten und der Bindungsenergien zwischen Nukleobasen auf der molekularen Ebene. Dabei können H-Brücken-Wechselwirkungen von pi-Stapel-Wechselwirkungen separiert werden. Ferner wird der Einfluss einzelner Wassermoleküle auf die Nukleobasen im molekularen Massstab untersucht (Nanohydratisierung). Diese grundlegenden Informationen können anschliessend für die Konstruktion genauerer Computermodelle von Biomolekülen verwendet werden.Projekt C: Exzitonische Wechselwirkungen in Gasphasen-DimerenIn der DNA kann die im UV absorbierte Anregungsenergie von einer Nukleobase zur nächsten wandern, und zwar in Stapelrichtung längs des DNA-Strangs oder zwischen den DNA-Strängen über die H-Brücken hinweg. Die Energie kann rasch (kohärent) oder langsam (inkohärent) wandern. Da beide Prozesse gleichzeitig ablaufen, sind sie am biologischen System sehr schwierig zu untersuchen. Wir untersuchen in isolierten und kalten molekularen Dimeren den kohärenten elektronischen Energieaustausch (exzitonischer Energietransfer) zwischen zwei Nukleobasen.Projekt D: Intermolekularer Protonen- und H-Atom-Transfer Protonen- und H-Atom-Transferprozesse sind zentral für das Verständnis vieler chemischer und biochemischer Prozesse: Protonentransfer in Wasser, Protonenleitung durch Membranproteine (Protonenpumpen), Energiegewinnung in der Atmungskette, chemi-osmotische Energiespeicherung, katalytische Primärprozesse in Enzymen). Solche Reaktionen sind schwierig zu beobachten, da die leichten Protonen sich sehr rasch und über ein ständig fluktuierendes Netzwerk von H-Brücken hinweg bewegen. Auf Grund dieser Schwierigkeiten wurden solche Reaktionen meist mit Computersimulationsmethoden untersucht. Um experimentelle Informationen über die Protonenleitung auf molekulare Stufe zu erhalten, verwenden wir Modellsysteme, die eine H-verbrückte Molekülkette enthalten. So können Protonen- bzw. H-Atom-Transfers auf molekularem Niveau und ohne störenden Einfluss der thermischen Bewegung untersucht werden.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Benchmarks for 0-0 transitions of aromatic organic molecules: DFT/B3LYP, ADC(2), CC2, SOS-CC2 and SCS-CC2 compared to high-resolution gas-phase data
Winter N, Graf N, Leutwyler S, Hättig C (2013), Benchmarks for 0-0 transitions of aromatic organic molecules: DFT/B3LYP, ADC(2), CC2, SOS-CC2 and SCS-CC2 compared to high-resolution gas-phase data, in Phys. Chem. Chem. Phys., 15, 6623-6630.
Building up Water-Wire Clusters: Isomer-Selective Ultraviolet and Infrared Spectra of Jet-Cooled 2-Aminopurine-(H2O)_n, n=2 and 3
Lobsiger S, Sinha RK, Leutwyler S (2013), Building up Water-Wire Clusters: Isomer-Selective Ultraviolet and Infrared Spectra of Jet-Cooled 2-Aminopurine-(H2O)_n, n=2 and 3, in J. Phys. Chem. B, 117, 12410-12421.
Excited-State Structure and Dynamics of Keto-Amino Cytosine: The 1pi-pi State is Nonplanar and its Radiationless Decay is Not Ultrafast
Lobsiger S, Sinha R, Frey HM, Leutwyler S (2013), Excited-State Structure and Dynamics of Keto-Amino Cytosine: The 1pi-pi State is Nonplanar and its Radiationless Decay is Not Ultrafast, in J. Phys. Chem. B, 117, 6106-6115.
NH3 as a Strong H-Bond Donor in Singly- and Doubly-Bridged Ammonia Solvent Clusters, 2-Pyridone-(NH3)n, n=1-3
Blaser S, Ottiger P, Frey HM, Leutwyler S (2013), NH3 as a Strong H-Bond Donor in Singly- and Doubly-Bridged Ammonia Solvent Clusters, 2-Pyridone-(NH3)n, n=1-3, in J. Phys. Chem. A, 117, 7523-7534.
Structure and Intermolecular Vibrations of Perylene-trans-1,2-Dichloroethene, a Weak Charge-Transfer Complex
Balmer F, Ottiger P, Pfaffen C, Leutwyler S (2013), Structure and Intermolecular Vibrations of Perylene-trans-1,2-Dichloroethene, a Weak Charge-Transfer Complex, in J. Phys. Chem. A, 117, 10702-10713.
Excitonic splitting and coherent electronic energy transfer in the gas-phase benzoic acid dimer
Ottiger P, Leutwyler S (2012), Excitonic splitting and coherent electronic energy transfer in the gas-phase benzoic acid dimer, in J. Chem. Phys., 137, 204303.
Isomer- and species selective infrared spectroscopy of jet-cooled 7H- and 9H-2-aminopurine and 2-aminopurine-H2O clusters
Sinha RK (2012), Isomer- and species selective infrared spectroscopy of jet-cooled 7H- and 9H-2-aminopurine and 2-aminopurine-H2O clusters, in J. Phys. Chem. A, 116, 1129-1136.
Out-of-Plane Low-Frequency Vibrations and Nonradiative Decay in the 1pi-pi* State of Jet-Cooled 5-Methylcytosine
Trachsel M, Lobsiger S, Leutwyler S (2012), Out-of-Plane Low-Frequency Vibrations and Nonradiative Decay in the 1pi-pi* State of Jet-Cooled 5-Methylcytosine, in J. Phys. Chem. B, 116, 11081-11091.
The Adiabatic Ionization Energy and Triplet T_1 Energy of Jet-Cooled Keto-Amino Cytosine.
Lobsiger S, Leutwyler S (2012), The Adiabatic Ionization Energy and Triplet T_1 Energy of Jet-Cooled Keto-Amino Cytosine., in J. Phys. Chem. Lett., 3, 3576-3580.
Vibrational quenching of excitonic splittings in H-bonded molecular dimers: Adiabatic description and effective mode approximation
Kopec S, Ottiger P, Leutwyler S, Köppel H (2012), Vibrational quenching of excitonic splittings in H-bonded molecular dimers: Adiabatic description and effective mode approximation, in J. Chem. Phys, 137, 184312.
Vibrational quenching of excitonic splittings in H-bonded molecular dimers: The electronic Davydov splittings cannot match experiment.
Ottiger P, Leutwyler S, Köppel H (2012), Vibrational quenching of excitonic splittings in H-bonded molecular dimers: The electronic Davydov splittings cannot match experiment., in J. Chem. Phys., 136(17), 174308.
Controlling Excited State Proton/H-Atom Transfer along Hydrogen Bonded Wires
C. Manca Tanner, C. Tanner, S. Leutwyler (2011), Controlling Excited State Proton/H-Atom Transfer along Hydrogen Bonded Wires, in G.-J. Zhao and K.-L. Han (ed.), 525-552.
Excitonic Splittings in Jet-Cooled Molecular Dimers
Ottiger P, Leutwyler S (2011), Excitonic Splittings in Jet-Cooled Molecular Dimers, in CHIMIA, 65(4), 228-230.
Intermolecular Clamping by Hydrogen Bonds: 2-Pyridone center dot NH3
Blaser S, Ottiger P, Lobsiger S, Frey HM, Leutwyler S (2011), Intermolecular Clamping by Hydrogen Bonds: 2-Pyridone center dot NH3, in CHEMPHYSCHEM, 12(10), 1841-1850.
Low-lying excited states and nonradiative processes of the adenine analogues 7H-and 9H-2-aminopurine
Lobsiger S, Sinha RK, Trachsel M, Leutwyler S (2011), Low-lying excited states and nonradiative processes of the adenine analogues 7H-and 9H-2-aminopurine, in JOURNAL OF CHEMICAL PHYSICS, 134(11), 114307-114321.
N-H center dot center dot center dot pi hydrogen-bonding and large-amplitude tipping vibrations in jet-cooled pyrrole-benzene
Pfaffen C, Infanger D, Ottiger P, Frey HM, Leutwyler S (2011), N-H center dot center dot center dot pi hydrogen-bonding and large-amplitude tipping vibrations in jet-cooled pyrrole-benzene, in PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 13(31), 14110-14118.
S0 and S1 State Structure, Methyl Torsional Barrier Heights, and Fast Intersystem Crossing Dynamics of 5-Methyl-2-hydroxypyrimidine
Lobsiger S, Frey HM, Leutwyler S, Morgan P, Pratt D (2011), S0 and S1 State Structure, Methyl Torsional Barrier Heights, and Fast Intersystem Crossing Dynamics of 5-Methyl-2-hydroxypyrimidine, in JOURNAL OF PHYSICAL CHEMISTRY A, 115(46), 13281-13290.
The S-1/S-2 exciton interaction in 2-pyridone center dot 6-methyl-2-pyridone: Davydov splitting, vibronic coupling, and vibronic quenching
Heid CG, Ottiger P, Leist R, Leutwyler S (2011), The S-1/S-2 exciton interaction in 2-pyridone center dot 6-methyl-2-pyridone: Davydov splitting, vibronic coupling, and vibronic quenching, in JOURNAL OF CHEMICAL PHYSICS, 135(15), 154311-154326.
Vibronic Spectra of Jet-Cooled 2-Aminopurine center dot H2O Clusters Studied by UV Resonant Two-Photon Ionization Spectroscopy and Quantum Chemical Calculations
Sinha RK, Lobsiger S, Trachsel M, Leutwyler S (2011), Vibronic Spectra of Jet-Cooled 2-Aminopurine center dot H2O Clusters Studied by UV Resonant Two-Photon Ionization Spectroscopy and Quantum Chemical Calculations, in JOURNAL OF PHYSICAL CHEMISTRY A, 115(23), 6208-6217.
Large-amplitude vibrations of an N-H center dot center dot center dot pi hydrogen bonded cis-amide-benzene complex
Pfaffen C, Frey HM, Ottiger P, Leutwyler S, Bachorz RA, Klopper W (2010), Large-amplitude vibrations of an N-H center dot center dot center dot pi hydrogen bonded cis-amide-benzene complex, in PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 12(29), 8208-8218.
Supersonic jet UV spectrum and nonradiative processes of the thymine analogue 5-methyl-2-hydroxypyrimidine
Lobsiger S, Frey HM, Leutwyler S (2010), Supersonic jet UV spectrum and nonradiative processes of the thymine analogue 5-methyl-2-hydroxypyrimidine, in PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 12(19), 5032-5040.

Collaboration

Group / person Country
Types of collaboration
Gruppe von Prof. Wim Klopper, Universität Karlsruhe Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
Gruppe von Prof. Horst Köppel, Universität Heidelberg Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
Gruppe von Prof. David Pratt, University of Pittsburgh United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
20th International Conference on Horizons in Hydrogen Bond Research Poster Modeling the Histidine-Phenylalanine Interaction: The NH···pi Hydrogen Bond of Imidazole·Benzene 15.09.2013 Antwerp, Belgium Leutwyler Samuel; Pfaffen Chantal;
20th International Conference on Horizons in Hydrogen Bond Research Poster Nanohydration of a Cis-Amide: Water Wires and Bridges 15.09.2013 Antwerp, Belgium Siffert Luca; Leutwyler Samuel; Ottiger Philipp;
Leopoldina Symposium Poster Supersonic Jet Spectroscopy of Perylene Charge-Transfer Complexes 11.09.2013 Zürich, Switzerland Balmer Franziska; Pfaffen Chantal; Ottiger Philipp; Leutwyler Samuel;
Fall Meeting of the Swiss Chemical Society Poster S1 → Tn Intersystem Crossing of 5,6-Trimethylenecytosine 06.09.2013 Lausanne, Switzerland Leutwyler Samuel;
Fall Meeting of the Swiss Chemical Society Talk given at a conference Fluorescence Lifetimes of Nucleobase Analogues using Picosecond Pump-Probe and Streak Techniques 06.09.2013 Lausanne, Switzerland Leutwyler Samuel;
Spring Meeting of the Swiss Association of Computational Chemistry Poster Computational Analysis of Weak Charge-Transfer Complexes 15.02.2013 Bern, Switzerland Pfaffen Chantal; Ottiger Philipp; Leutwyler Samuel;
48th Symposium on Theoretical Chemistry Poster Calculated and Experimental IR Spectra of Acid/Base clusters: 2-Pyridone·(NH3)n n=0-3 23.09.2012 Karlsruhe, Germany Ottiger Philipp; Leutwyler Samuel;
48th Symposium on Theoretical Chemistry Poster Computational Analysis of Medium-Strong Charge-Transfer Complexes 23.09.2012 Karlsruhe, Germany Leutwyler Samuel; Ottiger Philipp; Balmer Franziska; Pfaffen Chantal;
48th Symposium on Theoretical Chemistry Poster Modeling the Histidine-Phenylalanine Interaction: The NH···pi Hydrogen Bond of Imidazole·Benzene by Theory and Experiment 23.09.2012 Karlsruhe, Germany Pfaffen Chantal; Leutwyler Samuel;
CUSO summer school Poster Methyl Torsional Bands of the Jet-Cooled Adenine Analogue 9-Methyl-2-Aminopurine 20.08.2012 Villars-sur-Ollon, Switzerland Leutwyler Samuel;
CUSO Summer School Poster IR/UV-Depletion Spectroscopy of 2-Pyridone·(NH3)n n=0-3 Clusters 20.08.2012 Villars-sur-Ollon, Switzerland Leutwyler Samuel; Ottiger Philipp;
CUSO summer school Poster Supersonic Jet Spectroscopy of Weak Perylene-Based Charge-Transfer Complexes 20.08.2012 Villars-sur-Ollon, Switzerland Balmer Franziska; Pfaffen Chantal; Leutwyler Samuel;
International Conference in Isolated Biomolecules and Biomolecular Interactions (IBBI) Poster UV Spectra and Excited-State Relaxation of Cytosine and Cytosine Derivatives 22.01.2012 Les Diablerets, Switzerland Leutwyler Samuel;
Fall Meeting of the Swiss Chemical Society Poster S0 and S1 State Geometry and Methyl Torsional Barriers of 5-Methyl-2-hydroxypyrimidine 09.09.2011 Lausanne, Switzerland Leutwyler Samuel;
Fall Meeting of the Swiss Chemical Society Poster Supersonic Jet UV Spectra of Cytosine and 5-Fluorocytosine 09.09.2011 Lausanne, Switzerland Leutwyler Samuel;
Fall Meeting of the Swiss Chemical Society Poster Exciton splitting in molecular dimers: The jet-cooled 2-ketoquinoline dimer 09.09.2011 Lausanne, Switzerland Zambrino Giorgio Ivan; Leutwyler Samuel; Ottiger Philipp;
Fall Meeting of the Swiss Chemical Society Poster Supersonic Jet Spectroscopy of the Adenine Analogues 9-Methyl-2-aminopurine and 7-Methyl-2-aminopurine 09.09.2011 Lausanne, Switzerland Leutwyler Samuel;
CUSO summer school Poster N-H· · · pi hydrogen-bonding and large-amplitude tipping vibrations in jet-cooled pyrrole-benzene 21.08.2011 Villars-sur-Ollon, Switzerland Leutwyler Samuel; Ottiger Philipp; Pfaffen Chantal;
CUSO summer school Poster IR/UV-Depletion Spectroscopy of 2-Pyridone-(NH3)n Clusters 21.08.2011 Villars-sur-Ollon, Switzerland Leutwyler Samuel; Ottiger Philipp; Zambrino Giorgio Ivan;
CUSO summer school Poster Supersonic Jet Spectroscopy of Medium-Strong Charge-Transfer Complexes 21.08.2011 Villars-sur-Ollon, Switzerland Balmer Franziska; Pfaffen Chantal; Leutwyler Samuel;
Faraday Discussion 150 Poster Excitonic interaction in the 2-aminopyridine dimer 06.04.2011 Basel, Switzerland Leutwyler Samuel; Ottiger Philipp;
Faraday Discussion 150 Poster S0 and S1 State Geometry and Methyl Torsional Barriers of 5-Methyl-2-hydroxypyrimidine 06.04.2011 Basel, Switzerland Leutwyler Samuel;
Institutsseminar Individual talk Excitonic splittings in hydrogen bonded molecular dimers 25.01.2011 Würzburg, Germany Leutwyler Samuel;


Self-organised

Title Date Place
CUSO summer school on hydrogen bonds 20.08.2012 Villars-sur-Ollon, Switzerland

Awards

Title Year
Swiss Chemical Society Fall Meeting 2010 laureate; best talk in Physical Chemistry 2011

Associated projects

Number Title Start Funding scheme
130376 Ultraschnelle nichtlineare Raman-Messungen von Molekülen und Clustern 01.04.2010 Project funding (Div. I-III)
152816 Spektroskopie, Photophysik und Photochemie von Molekülclustern in Überschallmolekularstrahlen 01.04.2014 Project funding (Div. I-III)
121993 Spektroskopie, Photophysik und Photochemie von Molekülclustern in Überschallmolekularstrahlen 01.10.2008 Project funding (Div. I-III)

Abstract

Scientific goals:Project A: Experimental and theoretical investigations of supersonicallycooled nucleobases, nucleobase analogues and dimers of these. Determination of ground- and excited state rotational constants and geometries, vibrational and vibronic spectra, lifetimes, radiative and nonradiative pathways in the excited state. These will allow to understand the respective properties of the related nonfluorescent canonical nucleobases. The investigations of nucleobase base pairs will address the H-bonded topologies (Watson-Crick, reversed Watson-Crick, Wobble, Hoogsteen, sugar-edge), as well the hydrogen-bond vibrations and binding energies. Analogous investigations will also be undertaken on nanohydrated jet-cooled nucleobase analogues.Project B: Spectroscopy of T-shaped and pi-stacked aromatic dimers. Foraromatics that lack hydrogen-bonding groups, the energetic competition between T-shaped or ''herringbone'' arrangements and co-planar pi- stacking is a recurring theme in crystallography, materials chemistry and biochemistry. We propose systematic experimental and theoretical investigations of supersonically cooled T-shaped or pi-stacked aromatic dimers.Project C: Spectroscopic and theoretical investigations of symmetric homodimers. The theory of excitonic interactions in molecular dimers (with extensions to vibronic coupling) have been developed on the 1960s. So far, these theories and calculations have remained poorly tested by experiment. Our recent work on centrosymmetric hydrogen-bonded homodimers has shown the existing exciton/vibronic coupling theories must be extended to include (i) coupling to intermolecular vibrations, (ii) multimode vibronic coupling and (iii) vibronic quenching effects.Project D: Experimental and theoretical investigations of proton and H-atomtransfer reactions in supersonically cooled clusters, employing laser-triggered photoacids and hydrogen-bonding solvents. Investigation of proton and H-atom translocation along H-bonded solvent "wires". Determination of the temporal dependence and mechanisms of transfers using laser spectroscopic techniques, laser pico- and femtosecond kinetic methods and ab initio theoretical methods.
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