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
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Ottiger P, Leutwyler S (2011), Excitonic Splittings in Jet-Cooled Molecular Dimers, in CHIMIA
, 65(4), 228-230.
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.
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.
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.
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.
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.
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.
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.
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.
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.