Polish Academy of Sciences

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ON 2.5  Laser spectroscopy group

Spectroscopy of diatomic molecules



We are interested in…

→ molecular spectra

- they are measured using different spectroscopic techniques like polarisaton labelling spectroscopy (PLS), thermoluminescence and laser induced fluorescence (LIF), providing information concerning molecular features, molecular constants, energies of rovibrational levels in particular electronic states,...

A portion of a spectrum of KCs molecule recorded with PLS technique

A scheme of PLS experiment; rovibrational transitions between ground, and unknown, investigated electronic state are recorded

→ energy levels

- we measure wavelengths of transitions between rovibrational levels of two electronic states of different molecules to calculate energies of the levels

→ perturbations

- different types of interactions between molecular states are observed, appearing as irregularities in positions of energy levels, and line positions in molecular spectra

An example of perturbations observed for LiCs molecule: observed shifts of energy levels in the A1Σ+ state from their calculated positions

Potential evergy curves of several lowest electronic states of LiCs molecule

→ potential energy curves

- our goal is to construct potential energy curves of chosen electronic states, sometimes of very exotic shapes, which reproduce positions of measured energy levels, and enable calculations of other, not yet observed.