Imaginary time Path-integral techniques

People

Project coordinator: Sergei Ivanov
Co-workers: Sven Karsten, Julius Zimmermann

Project description

Classical approximation to nuclear dynamics is extremely robust, nonetheless it fails miserably in certain cases. Indeed, low temperatures, light reduced masses, shallow potential energy landscapes - all these circumstances often lead to the importance of nuclear quantum effects. Still, well-developed classical methods can be employed for simulating quantum objects by means of Feynman path integrals, that allow one to exactly map properties of a quantum object onto that of a more complicated but purely classical system. In the most primitive approximation, this classical system isomorphic to a quantum particle is the ring polymer with adjacent beads connected via harmonic springs. In more elaborate approximations the path in between the beads might be expanded in certain, e.g., Fourier series. This opens the doorway to obtain quantum thermodynamic properties of the system studied via genuinely classical approaches such as MD method. Further, even dynamic and, thus, spectroscopic properties can be obtained. The long-standing goal here is to develop a protocol of simulating molecular systems treating electrons and nuclei on equal footing.

Publications

  1. S. D. Ivanov, I. Grant, D. Marx
    Journal of Chemical Physics 143, 124304 (2015)[LINK]
    Quantum free energy landscapes from ab initio path integral metadynamics: Double proton transfer in the formic acid dimer is concerted but not correlated
  2. Sven Karsten (Master Thesis, 2014)
    Infrared Spectroscopy via Path Integral Techniques
  3. A. Witt, S. D. Ivanov, D. Marx
    Phys. Rev. Lett. 110, 083003 (2013) [LINK]
    Microsolvation–Induced Quantum Localization in Protonated Methane
  4. A. Witt, S. D. Ivanov, G. Mathias, D. Marx
    J. Phys. Chem. Lett. 2, 1377-1381 (2011) [LINK]
    Quantum Molecular Dynamics Calculations of Ultrafast Time Scales and Infrared Spectra of Protonated Methane: Quantifying Isotope-Specific Lifetimes
  5. S. D. Ivanov, O. Asvany, A. Witt, E. Hugo, G. Mathias, B. Redlich, D. Marx, S. Schlemmer
    Nature Chemistry 2, 298-302 (2010) [LINK]
    Quantum-induced symmetry breaking explains infrared spectra of CH5+ isotopologues
  6. S. D. Ivanov, A. Witt, M. Shiga, D. Marx
    J. Chem. Phys, 132, 031101 (2010) [LINK]
    Communications: On artificial frequency shifts in infrared spectra obtained from centroid molecular dynamics: Quantum liquid water
  7. A. Witt, S. D. Ivanov, M. Shiga, H. Forbert and D. Marx
    J. Chem. Phys. 130, 194510 (2009) [LINK]
    On the applicability of centroid and ring polymer path integral molecular dynamics for vibrational spectroscopy
  8. S. D. Ivanov, A. P. Lyubartsev
    J. Chem. Phys. 123, 034105 (2005) [LINK]
    Simulations of one- and two-electron systems by Bead-Fourier path integral molecular dynamics
  9. S. D. Ivanov, A. P. Lyubartsev, and A. Laaksonen
    Phys. Rev. E. 67, 066710 (2005) [LINK]
    Bead-Fourier path integral molecular dynamics
  10. P. N. Vorontsov-Velyaminov, R. I. Gorbunov, S. D. Ivanov
    Comp. Phys. Comm. 121, 64-66 (1999) [LINK]
    Bead-Fourier path integral Monte Carlo method applied to systems of identical particles