/research

research profile

The research context of this website is spectroscopy and conformational analysis of small molecules and molecular clusters, with a strong focus on matrix isolation IR spectroscopy and advanced anharmonic quantum chemical calculations. We aim to interpret complex vibrational spectra and understand molecular interactions, with applications in atmospheric chemistry and astrochemistry. This includes rationalizing spectral patterns of monomers, oligomers, and clusters, providing benchmarks for experimental assignments, and developing workflows for floppy and flexible molecules. In a broader context, our calculations aid the assignment of infrared action spectroscopy and predissociation spectroscopy as performed at the FELIX laboratory in Nijmegen.

Several research projects directly funded the presented work on this page. Matrix isolation and conformational sampling, investigating cluster formation relevant to new particle formation, including systems such as sulfuric acid, formic acid, and other organic molecules (FWF Project by Dominik Stolzenburg). Our work on weakly bound molecules involves characterization using millimeter-wave and infrared spectroscopy to understand non-covalent interactions (FWF Project by Dennis Dinu). We also study carbonic acid in detail, including its first matrix isolation and characterization by Jürgen Bernard (FWF Project by Thomas Loerting). Additionally, our research covers isotopic ratio analysis of N₂O, quantifying site-specific isotopic ratios using matrix-isolation IR spectroscopy integrated with large-scale European initiatives (MetHIR Project).

programs

Nomodeco A Decomposition scheme for the force constants and frequencies of molecular vibrations, which can be used to quantify the vibrational problem for larger systems.

PFIT in Molpro Fitting of spectroscopic parameters from rovibrational configuration interaction (RVCI) calculations for asymmetric tops using Watson's reduced operator.

theses

Julius Stolze, Matrix Isolation FTIR of aerosol precursors, BSc Thesis, TU Vienna (2025)

Jonas Schlagin , A novel approach to determine nitrous oxide isotopic ratios by means of matrix isolation IR spectroscopy, MSc Thesis, University of Innsbruck (2025)

Leonardo Pedri, Micellar Solvent Accessibility of Esterified Polyoxyethylene Chains as Crucial Element of Polysorbate Oxidation, MSc Thesis, University of Innsbruck (2025)

Christoph Teufl , Vibrational Band Assignment of the tt-Conformer of Carbonic Acid Monomethyl Ester (CAME) using Anharmonic Approaches, BSc Thesis, University of Innsbruck (2024)

Lukas Meinschad , Extension of a normal mode decomposition algorithm for the treatment of hydrogen-bonded molecular clusters, BSc Thesis, University of Innsbruck (2024)

Kemal Oenen , Basis Pruning Concepts within Rovibrational Configuration Interaction (RVCI) Calculations, MSc Thesis, University of Innsbruck (and Stuttgart) (2024)

Dennis F. Dinu , Rationalizing molecular vibration through matrix isolation infrared spectroscopy and vibrational configuration interaction computations, PhD Thesis, University of Innsbruck (2023)

Franziska Dahlmann, Spectroscopy of inter- and intramolecular vibrations in weakly bound ionic systems, PhD Thesis, University of Innsbruck (2023)

Ronny G. Kern, Developing a course on simple computational chemistry tools for Austrian high schools, MEd Thesis, University of Innsbruck (2023)

Luis Peters , Revision of molecular orbital theory in organic chemistry - organometallics, BSc Thesis, University of Innsbruck (2023)

Jonas Schlagin , Ab initio calculations of the anharmonic vibrational spectrum of carbonic acid - Bridging the gap between theory and experiment, BSc Thesis, University of Innsbruck (2023)

Kemal Oenen , Normal Mode Decomposition for the Evaluation of the Chemists Notation in Infrared Spectroscopy, BSc Thesis, University of Innsbruck (2022)

Steffen Spieler , Predissociation spectroscopy of weakly bound molecular ions in cryogenic traps, PhD Thesis, University of Innsbruck (2018)

Dennis F. Dinu , Anharmonic Vibrational Spectra of Small Organic Molecules and Halide-Hydrogen Complexes, MSc Thesis, University of Innsbruck (2018)

Jürgen Bernard, Solid and Gaseous Carbonic Acid, PhD Thesis, University of Innsbruck (2014)

publications

21. D. Comte, H. Kaur, D. F. Dinu, S. Alessandrini, L. Bizzocchi, K. R. Liedl, O. Asvany, S. Thorwirth, S. Schlemmer, C. Puzzarini, S. Brünken, M. Melosso, Action infrared spectroscopy of H2COH+ and H2COD+: Experimental and theoretical aspects. Chemical Physics Letters, (2026), 142719.
20. S. P. Melath, K. Dulitza, M. Hauck, D. Swaraj, F. Dahlmann, M. Gerlach, D. F. Dinu, P. Jusko, K. R. Liedl, S. Schlemmer, S. Brünken, R. Wester, Infrared predissociation spectroscopy of cold trapped C2H-(H2) and C2H-(D2). Molecular Physics, (2025), e2564248.
19. D. F. Dinu, B. Klein, C. Zhang, R. A. Talmazan, T. Loerting, H. Grothe, R. I. Kaiser, M. Podewitz, UV–Vis Spectra of Carbonic Acid: Rationalizing Experimental Redshifts between Monomer and Bulk based on (H2CO3)n Calculations. ChemPhysChem, 2500282, (2025).
18. C. Kieninger, K. Wurst, D. Leitner, L. P. Peters, D. F. Dinu, M. Wiedemair, M.-K. Zaretzke, M. Bröring, S. Hohloch, K. R. Liedl, B. Kräutler, Encasing the paramagnetic copper(II)-ion by the ring-contracted corrin ligand of vitamin B₁₂. Chemical Communications, (2025), Advance Article.
17. J. Weber, L. Pedri, L. P. Peters, P. K. Quoika, D. F. Dinu, K. R. Liedl, C. S. Tautermann, T. Diederichs, P. Garidel, Micellar solvent accessibility of esterified polyoxyethylene chains as crucial element of polysorbate oxidation: A density functional theory, molecular dynamics simulation and liquid chromatography/mass spectrometry investigation. Molecular Pharmaceutics, 22 (2025) 1348–1364.
16. L. Meinschad, K. Oenen, D. F. Dinu, K. R. Liedl, Toward less ambiguous vibrational spectroscopic notations for hydrogen-bonded water and methanol clusters. Journal of Molecular Spectroscopy, 408, 111997, (2025).
15. D.F. Dinu, K. Oenen, J. Schlagin, M. Podewitz, H. Grothe, T. Loerting, K. R. Liedl, How Vibrational Notations Can Spoil Infrared Spectroscopy: A Case Study on Isolated Methanol. ACS Physical Chemistry Au, 4, 6, 679-695, (2024).
14. D.F. Dinu, M. Ončák, S. Thorwirth, K.R. Liedl, S. Brünken, S. Schlemmer, P. Jusko, Zero-Point-Energy Driven Isotopic Exchange of the [H3O]− anion Probed by Mid-Infrared Action Spectroscopy. J. Am. Chem. Soc., 146, 31, 21634–21641 (2024).
13. J. Schlagin, D.F. Dinu, J. Bernard, T. Loerting, H. Grothe, K. R. Liedl, Solving the puzzle of the carbonic acid vibrational spectrum‐An anharmonic story. ChemPhysChem, e202400274 (2024).
12. K. Oenen, D. F. Dinu, K. R. Liedl, Determining internal coordinate sets for optimal representation of molecular vibration. J. Chem. Phys. 160, 014104 (2024).
11. E. Hildebrandt, V. Kahlenberg, H. Krüger, S. Wagner, D. F. Dinu, T. S. Hofer, P. Tropper, K. Liedl, Structural and computational studies on a quenchable high-temperature polymorph of magnesium tungstate (MgWO4-II). J. Solid State Chem. 327, 124269 (2023).
10. F. Dahlmann, D. F. Dinu, P. Jusko, C. Lochmann, T. Gstir, A. N. Marimuthu, K. R. Liedl, S. Brünken, R. Wester, Vibrational Predissociation Spectra of C2N− and C3N−: Bending and Stretching Vibrations. ChemPhysChem 24, 15 (2023).
9. R. Thaler, H. Kopacka, K. Wurst, T. Müller, D. F. Dinu, K. R. Liedl, F. R. Neururer, S. Hohloch, B. Bildstein, Borylated Cymantrenes and Tromancenium Salts with Unusual Reactivity. Organometallics, 41, 11, 1464-1473 (2022).
8. D. F. Dinu, M. Tschöpe, B. Schröder, K. R. Liedl, G. Rauhut, Determination of spectroscopic constants from rovibrational configuration interaction calculations. J. Chem. Phys. 157, 154107 (2022).
7. D. F. Dinu, P. Bartl, P. K. Quoika, M. Podewitz, K. R. Liedl, H. Grothe, T. Loerting, Increase of Radiative Forcing through Midinfrared Absorption by Stable CO2 Dimers? J. Phys. Chem. A, 126, 19 (2022).
6. D. F. Dinu, M. Podewitz, H. Grothe, T. Loerting, K. R. Liedl, On the synergy of matrix-isolation infrared spectroscopy and vibrational configuration interaction computations. Theor. Chem. Acc. 139, 1–15 (2020).
5. D. F. Dinu, M. Podewitz, H. Grothe, T. Loerting, K. R. Liedl, Decomposing anharmonicity and mode-coupling from matrix effects in the IR spectra of matrix-isolated carbon dioxide and methane. Phys. Chem. Chem. Phys. (2020)
4. D. F. Dinu, B. Ziegler, M. Podewitz, K. R. Liedl, T. Loerting, H. Grothe, G. Rauhut, The interplay of VSCF/VCI calculations and matrix-isolation IR spectroscopy – Mid infrared spectrum of CH3CH2F and CD3CD2F. J. Mol. Spectrosc. 367, 111224 (2020).
3. E.-M. Köck, J. Bernard, M. Podewitz, D. F. Dinu, R. G. Huber, K. R. Liedl, H. Grothe, E. Bertel, R. Schlögl, T. Loerting, Alpha carbonic acid revisited: Carbonic acid monomethyl ester as a solid and its conformational isomerism in the gas phase. Chem. – A Eur. J. (2019)
2. D. F. Dinu, M. Podewitz, H. Grothe, K. R. Liedl, T. Loerting, Toward Elimination of Discrepancies between Theory and Experiment: Anharmonic Rotational-Vibrational Spectrum of Water in Solid Noble Gas Matrices. J. Phys. Chem. A. 123, 8234–8242 (2019).
1. S. Spieler, D. F. Dinu, P. Jusko, B. Bastian, M. Simpson, M. Podewitz, K. R. Liedl, S. Schlemmer, S. Brünken, R. Wester, Low frequency vibrational anharmonicity and nuclear spin effects of Cl– (H2) and Cl– (D2). J. Chem. Phys. 149, 174310 (2018).