Dr. Ralph Welsch

Center for Free-Electron Laser Science

bldg. 99 / room 03.018



Curriculum Vitae


Ralph got his B.Sc. and M.Sc. in “Naturwissenschaftlicher Informatik” (Informatics in the natural sciences) from Bielefeld University in 2009 and 2011, respectively. In 2014 he received his Ph.D. in Chemistry for his work on “Fully state-resolved quantum dynamics and ro-vibrational control of the chemical reactivity in H + CH4 → H2 + CH3“. In 2015 Ralph joined the Miller Group at Caltech as a DFG research scholar, where he worked on a variety of topics including approximate quantum dynamics and 2D-THz spectroscopy. Ralph was appointed as staff scientist in the CFEL-DESY theory division leading the chemical dynamics subgroup in 2017.


Quantenchemie III / Quantum Dynamics in Chemistry

Winter term 2017/2018



Details can also be found on my Google scholar profile or via ResearchID K-4276-2012..

* marks equal contribution.


  1. P. Mishra, V. Bettaque, O. Vendrell, R. Santra, and R. Welsch, "Prospects of Using High-Intensity THz Pulses To Induce Ultrafast Temperature-Jumps in Liquid Water", J. Phys. Chem. A 122, 5211 (2018)
  2. R. Welsch, "Rigorous Close-Coupling Quantum Dynamics Calculation of Thermal Rate Constants for the Water Formation Reaction of H2+OH on a High-Level PES", J. Chem. Phys. 148, 204304 (2018) (Editor's Pick)
  3. P. Zalden, L. Song, X. Wu, H. Huang, F. Ahr, O. Muecke, J. Reichert, M. Thorwart, P. Mishra, R. Welsch, R. Santra, F. Kärtner, and C. Bressler, "Molecular polarizability anisotropy of liquid water revealed by terahertz-induced transient orientation", Nat. Commun. 9, 2142 (2018)
  4. C. Arnold, O. Vendrell, R. Welsch, and R. Santra, "Control of Nuclear Dynamics through Conical Intersections and Electronic Coherences", Phys. Rev. Lett. 120, 123001 (2018)
  5. S. Bazzi, R. Welsch, O. Vendrell, and R. Santra, "Challenges in XUV Photochemistry Simulations: A Case Study on Ultrafast Fragmentation Dynamics of the Benzene Radical Cation", J. Phys. Chem. A 122, 1004 (2018)


  1. I. A. Finneran*, R. Welsch*, M. A. Allodi, T. F. Miller, and G. A. Blake, "2D THz-THz-Raman Photon-Echo Spectroscopy of Molecular Vibrations in Liquid Bromoform", J. Phys. Chem. Lett. 8, 4640 (2017)


  1. R. Welsch, K. Song, Q. Shi, S. C. Althorpe, and T. F. Miller III, "Non-equilibrium quantum correlation functions from RPMD and CMD", J. Chem. Phys. 145, 204118 (2016)
  2. R. Welsch, E. Driscoll, J. M. Dawlaty, and T. F. Miller III, "Molecular seesaw: How increased hydrogen bonding can hinder excited-state proton transfer", J. Phys. Chem. Lett. 7, 3616 (2016)
  3. I. A. Finneran, R. Welsch, M. A. Allodi, T. F. Miller, and G. A. Blake, "Coherent two-dimensional Terahertz-Terahertz-Raman spectroscopy", Proc. Natl. Acad. Sci. USA 113, 6857 (2016)


  1. R. Welsch and U. Manthe, "Full-dimensional and reduced-dimensional calculations of initial state-selected reaction probabilities studying the H + CH4 → H2 + CH3 reaction on a neural network PES", J. Chem. Phys. 142, 064309 (2015)
  2. R. Welsch and U. Manthe, "Loss of memory in H + CH4 → H2 + CH3 state-to-state reactive scattering", J. Phys. Chem. Lett. 6, 338 (2015)


  1. R. Welsch and U. Manthe, "The role of the transition state in polyatomic reactions: Initial stateselected reaction probabilities of the H+CH4 → H2+CH3 reaction", J. Chem. Phys. 141, 174313 (2014)
  2. R. Welsch and U. Manthe, "Communication: Ro-vibrational control of chemical reactivity in H + CH4 → H2 + CH3 : Full-dimensional quantum dynamics calculations and a sudden model", J. Chem. Phys. 141, 051102 (2014)
  3. U. Manthe and R. Welsch, "Correlation functions for fully or partially state-resolved reactive scattering calculations", J. Chem. Phys. 140, 244113 (2014)


  1. R. Welsch and U. Manthe, "Fast Shepard interpolation on graphics processing units: Potential energy surfaces and dynamics for H + CH4 → H2 + CH3", J. Chem. Phys. 138, 164118 (2013)


  1. R. Welsch and U. Manthe, "Reaction dynamics with the multi-layer multi-congurational timedependent hartree approach: H + CH4 → H2 + CH3 rate constants for dierent potentials", J. Chem. Phys. 137, 244106 (2012)
  2. R. Welsch and U. Manthe, "Thermal flux based analysis of state-to-state reaction probabilities", Mol. Phys. 110, 703 (2012) (William H. Miller Festschrift)
  3. R. Welsch, F. Huarte-Larranaga, and U. Manthe, "State-to-state reaction probabilities within the quantum transition state framework", J. Chem. Phys. 136, 064117 (2012)
  4. H. Ndome, R. Welsch, and W. Eisfeld, "A new method to generate spin-orbit coupled potential energy surfaces: Eective relativistic coupling by asymptotic representation", J. Chem. Phys. 136, 034103 (2012)


  1. W. Schenck, R. Welsch, A. Kaiser, and R. Möller, "Adaptive learning rate control for Neural Gas Principal Component Analysis"", in ESANN 2010 proceedings | European Symposium on Artificial Neural Networks (d-side publications, Bruges (Belgium), 2010).