Replacement of an existing Vibrational Circular Dichroism spectrometer.

In 2003, an FWO project of W. Herrebout (Molecular Spectroscopy) and P. Bultinck (Ghent Quantum Chemistry Group, Ghent University) led to the purchase of a Bruker PMA37 module. The module was connected to an existing Bruker IFS66v FTIR spectrometer purchased in 1998. Apart from standard infrared spectra, the combination of an FTIR research spectrometer and a dedicated PMA37 polarisation accessory allowed to obtain vibrational circular dichroism (VCD) spectra, in which small differences in absorbance of left and right circularly polarised IR light by a chiral sample are detected. Continuous maintenance of the FTIR instrument, including updates of the dedicated PC in 2003 and 2011, and tedious re-alignment of the optical bench of the VCD accessory by the local PI at regular intervals, allowed the set-up to be used for research and fee-for-service activities on an almost continuous basis up to 2019. In June 2019, electronic problems with the acquisition card controling the optical bench of the Bruker IFS66v FTIR spectrometer was detected. Discussions with E. Huys, FTIR service engineer at Bruker Belgium, and the engineers responsible at the Bruker Optics headquarters in Ettlingen (Germany) finally led to the conclusion that due to the out-dated electronics used in the FTIR spectrometer, the current set-up could no longer be supported. Moreover, taking into account further developments of the VCD module, including amongst others, the use of a more recent piezoelectric modulator working at a significantly higher frequency (42 kHz in the more recent PMA50 vs. 37 kHz in the older PMA37), and the use of more developed acquisition cards and electronics replacing the existing lock-in amplifier currently used in the PMA37 module, the existing module unfortunately could not be coupled to the Vertex or Inventio-R FTIR spectrometers currently supplied by Bruker Optics. To allow the research lines involving vibrational circular dichroism to be further developed, and to ensure the existing local and international fee-for-service activities employing VCD, in the current proposal, financial support allowing the replacement of the current set-up is requested.

Keywords:VIBRATIONAL CIRCULAR DICHROISM (VCD), RAMAN OPTICAL ACTIVITY, INFRARED SPECTROSCOPY

Disciplines:Physical organic chemistry