Abstract book - Prof. Per Jensen, Ph.D. - Bergische Universität ...

Poster session, J4 167Zeeman effects in open-shell van der Waals complexesSarantos Marinakis 1 , Brian J. Howard 11 Department of Chemistry, The Physical and Theoretical Chemistry Laboratory,University of Oxford, South Parks Road, Oxford, OX1 3QZ, United Kingdom,sarandis.marinakis@chem.ox.ac.uk;Marinakis S.Howard B.J.Nitric oxide (NO) molecules play a key role in atmospheric phenomena, interstellarspace and combustion. In biological systems, NO plays a significant beneficial role in avariety of processes including vascular relaxation, anti-tumour and anti-pathogenresponse, mitochondrial respiration, and it is a ubiquitous signalling molecule in thecardiovascular system (Nobel Prize in Physiology and Medicine (1998). However,detailed studies of NO complexes are required for a quantitative modelling of thesemedia.The aim of the present work is to study the lower bound states of Rg-NO open-shell vander Waals complexes using Fourier Transform Microwave Spectroscopy (FTMS). Theexperiments employ a pulsed supersonic expansion of gas mixture (Ne/NO) into aFabry-Perot cavity. The frequency range covered the region between 6 and 18 GHz.Three pairs of mutually perpendicular Helmholtz coils were used to generate a near-nullfield in the centre of spectrometer. In this way, magnetic-field-free spectra wererecorded, and we report here some new transitions not observed in the first FTMS studyof NeNO 1 . Our results are analysed using a rigid model, and a dynamical one, whichtakes into account the large amplitude vibrational motion.In addition to this, we present the first systematic study of magnetic effects on thiscomplex. In this case, the Helmholtz coils were used to augment the Earth’s magneticfield and spectra up to 3.6 Gauss were recorded. The effect of weak magnetic fields wasexamined using two geometries: a) the magnetic field being parallel to the electric field(thus allowing ΔΜ F =0 transitions), b) the magnetic field being perpendicular to theelectric field (thus allowing ΔΜ F =±1 transitions). There are no previous studies onmagnetic properties of complexes of open shell molecules that need multiple potentialenergy surfaces (PESs) to be described, and especially with hyperfine resolution. Suchmeasurements could provide additional information on the nature of the intermolecularpotential surface, and especially on the difference potential. The absolute values for theg-factors for many rotational levels have been obtained and their rotational dependenceis discussed 2 .We hope that our work will inspire further quantitative work in weak magnetic effectsof free radicals complexes.References[1] Y. Sumiyoshi, Y. Endo, J. Phys. Chem. A 114, 4798, 2010[2] S. Marinakis, B. J. Howard, manuscript in preparation