Michael Welzel

Research

Quality Assurance of Research Software
In particular, the maintenance, quality assurance and improvement of the program codes Vibrations/LocVib for the calculation of anharmonic vibration spectra. In addition, to make the code useable for a broad scientific community.

Complex scaling in quantum chemistry
Resonances are metastable states embedded in a continuum. In conventional quantum mechanics (Hermitian QM), resonances are hidden in this continuum. A Hamiltonian operator describing resonances is non-Hermitian and the eigenvalues of the corresponding Schrödinger equation are complex.

Balslev and Combes developed an elegant method in which the coordinates of atoms and molecules are complex scaled (complex scaling). Using this method, the continuum rotates in the complex plane, the resonances are uncovered, and also the complex energies are obtained. In quantum chemical calculations one uses the variational principle, where I apply the complex scaling and study in particular the behavior of the solutions depending on the basis functions used.

Curriculum Vitae

• since 04/2022:  Postdoc (Research Software Engineer) in the working group of Prof. Dr. Christoph Jacob, TU Braunschweig
• 10/2017 – 03/2022:  Ph.D. student in the Jacob group, TU Braunschweig
• 10/2014 – 04/2020:  Bachelor of Science, Mathematics, TU Braunschweig
• 10/2015 – 08/2017:  Master of Science, Chemistry, TU Braunschweig
• 10/2011 – 08/2015:  Bachelor of Science, Chemistry, TU Braunschweig

Conferences und Workshops

• 03/2018:  MMQC – Modern Methods in Quantum Chemistry, Mariapfarr
  Talk: Complex Scaling for one-dimensional model systems
• 03/2018:  ADF Developer Meeting,
  (SCM: Software for Chemistry & Materials), Amsterdam
• 10/2018:  MWM – Modern Wave function Methods in Electronic Structure Theory, Summer School, Gelsenkirchen
• 09/2018:  STC – Symposium on Theoretical Chemistry, Halle
  Poster: Complex Scaling for one-dimensional model systems
• 03/2019:  WAMCC - Workshop on Advanced Methods in Quantum Chemistry
• 03/2019:  Coderefinery Workshop, Stockholm
• 03/2017:  MMQC – Modern Methods in Quantum Chemistry, Mariapfarr
  Talk: Complex Scaling
• 05/2017:  JCT – Jung Chemiker Tagung, Braunschweig
  Poster: Complex Scaling

Miscellaneous

• WS 2015/16:  Scientific assistent for Prof. Hohm

University Politics: 

• 09/2016 – 06/2017:  Study Committee Mathematics
• 04/2019 – (03/2021):  Ph.D. students representative faculty 2:
  Council of Ph.D. students,
  Faculty Council,
  Doctoral Committee

2: Complex Scaling in Quantum Chemistry

Michael Welzel

Verlag Dr. Hut
München, 2022
SBN 978-3-8439-5057-2

1: Towards Theoretical Spectroscopy with Error Bars: Systematic Quantification of the Structural Sensitivity of Calculated Spectra

Tobias G. Bergmann, Michael Ole Welzel and Christoph R. Jacob

Chem. Sci. 11 (2020), 1862–1877

Online-Version PDF