Chirped Pulse Fourier Transform Spectroscopy for Astrophysics

  • Our Team

  • Prof. S. Schlemmer (PI, PH1)
  • Marius Herrmanns (PH1)
  • Elena Zakharenko (PH1)
  • Nadine Wehres (PH1)
  • Guests:
  • Isabel Pena (University Valladolid/Spain)
  • Jens-Uwe Grabow (Leibniz Universität, Hannover)
  • Former member:
  • Alexey Potapov (PH1)

A short overview

Chirped Pulse Fourier Transform Spectroscopy (CP-FTS) is a rather new technique of molecular spectroscopy which enables i) recording of broad band spectra in the centimeter and millimeter wavelength ranges and ii) fast excitation and data acquisition which allows to record time dependent signals. The latter opens new experimental studies such as collision kinetics of spectrally identified molecules or 2D pump-probe spectroscopy which helps assigning complex spectra. Both aspects are addressed in this project as outlined below. This project has been started in the second funding period with building various instruments. The main results are CP-FT spectra of jet-cooled molecules in the range 12-26 GHz and first spectra also obtained in the 100 GHz range. The sensitive laboratory emission spectrometers built in collaboration between B3, B4, D3 and project S shall serve as advanced receivers for future CP-FTS experiments. State-to-state rate coefficients for NH3 self collisions have been determined using the CP-FTS instruments. In the initial funding period the spectroscopy of several binary complexes such as NH3 - HD have been investigated in detail in order to determine the potential energy surface (PES). More broad band spectra of complex molecules shall be recorded and analysed in the future on a routine basis using a cold collision gas cell permitting studies at temperatures as low as 4 K. Also more collision experiments of the system NH3 + H2 and He shall be conducted to help interpreting astrophysical observations within CRC956.


Selected Publications


2018

  • N. Wehres, M. Hermanns, O. H. Wilkins, K. Borisov, F. Lewen, J.-U. Grabow, S. Schlemmer, and H. S. P. Müller, Rotational spectroscopy of the two conformers of 3-methylbutyronitrile (C4H9CN) between 2 and 400 GHz, Astron. Astrophys. (2018), in press.
  • N. Wehres, J. Maßen, K. Borisov, B. Schmidt, F. Lewen, U. U. Graf, C. E. Honingh, D. R. Higgins, and S. Schlemmer, A Laboratory Heterodyne Emission Spectrometer at Submillimeter Wavelengths, Phys. Chem. Chem. Phys. 20, 5530–5544 (2018)
  • N. Wehres, B. Heyne, F. Lewen, M. Hermanns, B. Schmidt, C. Endres, U. U. Graf, D. R. Higgins, and S. Schlemmer, “100 GHz Room-Temperature Laboratory Emission Spectrometer”, Proceedings of the IAU Symposium No. 332 “Astrochemistry VIII: Through the Cosmos from Galaxies to Planets ”, preprint.
  • L. A. Surin, I. V. Tarabukin, S. Schlemmer, Y. N. Kalugina, and A. van der Avoird, Ab initio Potential and Rotational Spectra of the CO–N2 Complex, J. Chem. Phys. 148, Art. No. 044313 (2018)

2017

  • H. S. P. Müller, O. Zingsheim, N. Wehres, J.-U. Grabow, F. Lewen, and S. Schlemmer, “Rotational Spectroscopy of the Lowest Energy Conformer of 2-Cyanobutane”, J. Phys. Chem. A 121, 7121 (2017).
  • L. A. Surin, I. V. Tarabukin, S. Schlemmer, A. A. Breier, T. F. Giesen, M. C. McCarthy, and A. van
    der Avoird, “Rotational Spectroscopy of the NH3–H2 Molecular Complex”, ApJ 838, 27 (2017).

2016

  • Potapov, A. and Sánchez-Monge, Á. and Schilke, P. and Graf, U. U. and Möller, T. and Schlemmer, S., The CO–H2 van der Waals complex and complex organic molecules in cold molecular clouds: A TMC-1C survey, Astron. Astrophys. 594, Art. No. A117 (2016)
  • S. Thorwirth, M. A. Martin-Drumel, C. P. Endres, T. Salomon, O. Zingsheim, J. van Wijngaarden, O. Pirali, S. Gruet, F. Lewen, S. Schlemmer, and M. C. McCarthy, “An ASAP treatment of vibrationally excited S2O: The v3 mode and the v3 + v2 - v2 hot band”, J. Mol. Spectrosc. 319, 47 (2016).

2015

  • A. Potapov, L. Surin, and S. Schlemmer, First observation of the rotational spectrum of the HD–CO weakly bound complex, J. Mol. Spectrosc. 307, 18–19 (2015)
  • L. A. Surin, A. Potapov, H. S. P. Müller, and S. Schlemmer, A New Millimeter-wave Observation of the Weakly Bound CO–N2 Complex, J. Mol. Spectrosc. 307, 54–58 (2015)
  • L. A. Surin, A. Potapov, A. A. Dolgov, I. V. Tarabukin, V. A. Panfilov, S. Schlemmer, Y. N. Kalugina, A. Faure, and A. van der Avoird, Rotational study of the NH3–CO complex: Millimeter-wave measurements and ab initio calculations, J. Chem. Phys. 142, Art. No. 114308 (2015)
  • L. A. Surin, I. V. Tarabukin, V. A. Panfilov, S. Schlemmer, Y. N. Kalugina, A. Faure, C. Rist, and A. van der Avoird, Rotational study of the CH4–CO complex: Millimeter-wave measurements and ab initio calculations, J. Chem. Phys. 143, Art. No. 154303 (2015)