Scientific background

Ions play a key role in the chemical evolution of our universe. The process of star and planet formation is
tightly connected to the presence and abundance of these species. Their spectra turn into diagnostic tools for
various astrophysical environments and their temporal evolution. However, laboratory spectra of most ions
relevant to astrophysics are not available. Moreover, predicted spectra from ab-initio theory are not nearly
accurate enough to guide astrophysical searches. Therefore, corner stones for our understanding of chemistry
in the interstellar medium are missing. In sharp contrast, highly sensitive telescopes with large collection
areas are ready to find these species in space.

Goals and scientific program

In order to make this important next step in molecular astrophysics I propose to record high-resolution
spectra from the microwave to visible range using our unique and innovative light induced reactions (LIR)
methods in ion traps. It is molecule specific through mass selection, many orders of magnitude more
sensitive and less complex due to buffer gas cooling as compared to conventional methods.
High-resolution spectroscopy is the most accurate discipline in quantitative sciences and for molecules it is
linked to highly accurate molecular structures, bond lengths and angles. But this fundamental concept is put
into question for very floppy molecules, e.g. protonated methane, one of the key missing ions in space.
Therefore, also new models describing the structure and internal dynamics of molecules shall be developed
in this interdisciplinary project.

Based on the laboratory spectroscopy in this project new molecules will be found in space. We shall unravel
the role of the most important missing ions which will have great impact on the interpretation of
astrophysical observations. At the same time understanding the spectra of the missing ions will challenge the
current concept of molecular structure and thus lead to an advancement of molecular physics as a whole.

Publications

• 2024
  • High Resolution Rovibrational Spectroscopy of the ν₆ and ν₃ + ν₇ Bands of H₂CCCH⁺,
    J. L. Doménech, W. G. D. P. Silva. E. A. Michael, S. Schlemmer, and O. Asvany,
    J. Phys. Chem. A, 128, 10322–10327 (2024).
  • High resolution rovibrational and rotational spectroscopy of H₂CCCH⁺,
    W. G. D. P. Silva, D. Gupta, E. Plaar, J. L. Doménech, S. Schlemmer, and O. Asvany,
    Mol. Phys., 122, e2296613 (2024).
  • Hyperfine-resolved rotational spectroscopy of HCNH⁺,
    W. G. D. P. Silva, L. Bonah, P. C. Schmid, S. Schlemmer, and O. Asvany,
    J. Chem. Phys., 160, 071101 (2024).
  • High-resolution spectroscopy of the ν₃ antisymmetric C–H stretch of C₂H₂⁺ using leak-out action spectroscopy,
    S. Schlemmer, E. Plaar, D. Gupta, W. G. D. P. Silva, T. Salomon, and O. Asvany,
    Mol. Phys., 122, e2241567 (2024).
  • Gas-Phase Infrared Action Spectroscopy of CH₂Cl⁺ and CH₃ClH⁺: Likely Protagonists in Chlorine Astrochemistry,
    S. Thorwirth, K. Steenbakkers, T. Danowski, P. C. Schmid, L. Bonah, O. Asvany, S. Brünken, and S. Schlemmer,
    Molecules, 29, 665 (2024).
• 2023
  • High resolution rovibrational and rotational spectroscopy of H2CCCH⁺,
    W. G. D. P. Silva, D. Gupta, E. Plaar, J. L. Doménech, S. Schlemmer and O. Asvany,
    Mol. Phys., e2296613 (2023).
  • Astronomical CH₃⁺ rovibrational assignments — A combined theoretical and experimental study validating observational findings in the d203-506 UV-irradiated protoplanetary disk,
    P. B. Changala, N. L. Chen, H. L. Le, B. Gans, K. Steenbakkers, T. Salomon, L. Bonah, I. Schroetter, A. Canin, M.-A. Martin-Drumel, U. Jacovella, E. Dartois, S. Boyé-Péronne, C. Alcaraz, O. Asvany, S. Brünken, S. Thorwirth, S. Schlemmer, J. R. Goicoechea, G. Rouillé, A. Sidhu, R. Chown, D. Van De Putte, B. Trahin, F. Alarcón, O. Berné, E. Habart, and E. Peeters,
    Astron. Astrophys., 680, A19 (2023).
  • Ro-vibrational spectra of C≡C stretching modes of C₃H⁺ and HC₃O⁺,
    M. Bast, J. Böing, T. Salomon, S. Thorwirth, O. Asvany, M. Schäfer, and S. Schlemmer,
    J. Mol. Spectrosc., 398, 111840 (2023).
  • Formation of the methyl cation by photochemistry in a protoplanetary disk, O. Berné, M.-A. Martin-Drumel, I. Schroetter, J. R. Goicoechea, U. Jacovella, B. Gans, E. Dartois, L. H. Coudert, E. Bergin, F. Alarcon, J. Cami, E. Roueff, J. H. Black, O. Asvany, E. Habart, E. Peeters, A. Canin, B. Trahin, C. Joblin, S. Schlemmer, S. Thorwirth, J. Cernicharo, M. Gerin, A. Tielens, M. Zannese, A. Abergel, J. Bernard-Salas, C. Boersma, E. Bron, R. Chown, S. Cuadrado, D. Dicken, M. Elyajouri, A. Fuente, K. D. Gordon, L. Issa, O. Kannavou, B. Khan, O. Lacinbala, D. Languignon, R. Le Gal, A. Maragkoudakis, R Meshaka, Y. Okada, T. Onaka, S. Pasquini, M. W. Pound, M. Robberto, M. Röllig, B. Schefter, T. Schirmer, A. Sidhu, B. Tabone, D. Van De Putte, S. Vicente, and M. G. Wolfire,
    Nature, 621, 56–59 (2023).
  • High-resolution rovibrational and rotational spectroscopy of the singly deuterated cyclopropenyl cation, c-C₃H₂D⁺,
    D. Gupta, W. G. D. P. Silva, J. L. Doménech, E. Plaar, S. Thorwirth, S. Schlemmer, and O. Asvany,
    Faraday Discuss., 245, 298–308 (2023).
  • Discovery of H₂CCCH⁺ in TMC-1,
    W. G. D. P. Silva, J. Cernicharo, S. Schlemmer, N. Marcelino, J.-C. Loison, M. Agúndez, D. Gupta, V. Wakelam, S. Thorwirth, C. Cabezas, B. Tercero, J. L. Doménech, R. Fuentetaja, W.-J. Kim, P. de Vicente, and O. Asvany,
    Astron. Astrophys., 676, L1 (2023).
  • High-resolution ro-vibrational and rotational spectroscopy of HC₃O⁺,
    O. Asvany, S. Thorwirth, P. C. Schmid, T. Salomon, and S. Schlemmer,
    Phys. Chem. Chem. Phys., 25, 19740–19749 (2023).
• 2022
  • Leak-out Spectroscopy, A Universal Method of Action Spectroscopy in Cold Ion Traps,
    P. C. Schmid, O. Asvany, T. Salomon, S. Thorwirth, and S. Schlemmer,
    J. Phys. Chem. A, 126, 8111–8117 (2022).