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English
Deutsch
Research projekts
My main research interests concern molecular dynamics in its broadest sense.
In any case a special attention is turned to the connection and the fruitful interplay between experiment and theory for the study of fundamental inter-molecular and intra-molecular dynamic processes.
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One of my research interest is the inter-molecular dynamics in fluids. With classical MD simulations we investigate the mass ratio dependence of the self-diffusion coefficient D in pure atomic fluids and mixtures (e.g. [1]). A very recent project is the investigation of the so called dynamic isotope effect in molecular fluids and we introduce a generalized approach to estimate the influence of the translation-rotation coupling on the corresponding self-diffusion coefficients [2]. |
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My second research field deals with the derivation of the intra-molecular vibrational energy redistribution (IVR) dynamics after vibrational excitation in a molecule by a combined approach of high resolution spectroscopy and ab initio calculations. We have established in the last years new coupling mechanisms across bonds, which are important for the IVR process for e.g. CF3CHFI [3], CHD2OH [4] and HCOOH [5]. Current projects regarding CHClF2 [6] and CH3I. |
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The third research area concerns the even more fundamental process of stereomutation tunneling dynamics e.g. in helical chiral H2O2 like molecules. We have shown that parity violation mediated by the weak interaction influences or even dominated this dynamics in some molecules, such as Cl2O2 [7], Cl2S2 [8], H2Se2 [9] or H2Te2 [10]. Such molecules are potential candidates for the first experimental determination of molecular parity violation, which would allow for an alternative approach (instead of particle accelerator experiments) for the determination of parameters of the standard model of high energy physics and is also a stringent test of the parity violating Hamiltonian used. We have done corresponding investigations also for molecules which are chiral only by isotopic substitution [11,12]. |
For an overview of the last two fields see e.g. the review [13].
[1] Martin Willeke. “Limits of the validity of the mass ratio independence of the Stokes-Einstein relation: molecular dynamics calculations and comparison with the Enskog theory.” Mol. Phys. 101: 1123-1130 (2003).
[2] Martin Willeke. “Translation-Rotation Coupling in the Self-Diffusion of Fluids: Molecular Dynamic Investigation and a Generalized Exponential Approach.” Mol. Phys., 103: 1353-1360 (2005).
[3] Martin Quack and Martin Willeke. “Ab initio calculations for the anharmonic vibrational resonance dynamics in the overtone spectra of the coupled OH and CH chromophores in CD2H-OH.” J. Chem. Phys. 110: 11958-11970 (1999).
[4] Jörg Pochert, Martin Quack, Jürgen Stohner and Martin Willeke. “Ab initio Calculation and spectroscopic analysis of the intramolecular vibrational redistribution in 1,1,1,2-tetrafluoroiodoethane CF3CHFI.” J. Chem. Phys. 113: 2719-2735 (2000).
[5] David Luckhaus, Martin Quack, and Martin Willeke. “Coupling Across Bonds: Ab initio Calculations for the Anharmonic Resonance Dynamics of the Coupled OH and CH Chromophores in Trans Formic Acid HCOOH.” Z. Physik. Chem. 214: 1087-1114 (2000).
[6] Sieghard Albert, Hans Hollenstein, Martin Quack and Martin Willeke. “Doppler-limited FTIR spectrum of the ν3(a')/ν8(a'') Coriolis resonance dyad of CHClF2 obtained with a new Bruker IFS 120vHR Spectrometer, and comparison with ab initio calculations.” Mol.~Phys., 102: 1671-1686 (2004).
[7] Martin Quack and Martin Willeke, “Stereomutation tunneling switching in Chlorineperoxide ClOOCl.”, J. Phys. Chem. A, 110: 3338-3348 (2006).
[8] Robert Berger, Michael Gottselig, Martin Quack and Martin Willeke. “Parity Violation Dominates the Dynamics of Chirality in Dichlorodisulfane.“ Angew. Chem. Int. Ed. (English), 40: 4195-4198 (2001).
[9] Michael Gottselig, Martin Quack, Jürgen Stohner and Martin Willeke. “Mode-selective stereomutation tunneling and parity violation in HClOH+ and H2Te2 isotopomers.” Int.~J.~Mass Spectrometry, 233: 373-384 (2004).
[10] Michael Gottselig, Martin Quack and Martin Willeke. “Mode-selective stereomutation tunneling as compared to parity violation in hydrogen diselenide isotopomers 1,2,3H280Se2.” Isr.~J.~Chem., 43: 353-362 (2003).
[11] Robert Berger, Martin Quack, Achim Sieben, and Martin Willeke. “Parity violating potentials for the torsional motion of methanol and its isotopomers (CH3OH, CD3OH, 13CD3OH, CH3OD, CH3OT, CHD2OH and CHDTOH).” Helv. Chim. Acta, 86: 4048–4060 (2003).
[12] Robert Berger, Guido Laubender, Martin Quack, Achim Sieben, Jürgen Stohner and Martin Willeke. "Isotopeneffekte durch Paritätsverletzung in chiralen Molekülen." Angew. Chem., 117: 3689-3693 (2005).
[13] Jürgen Stohner, Martin Quack, Martin Willeke, "High-resolution spectroscopic studies and theory of parity violation in chiral molecules", ANNUAL REVIEW OF PHYSICAL CHEMISTRY, 59: 741-769 (2008).
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