Hydrogen doppler spectroscopy using ¹⁵N ions

Abstract:

The energy spread of atomic and molecular ion beams from the 4 MV Dynamitron tandem accelerator at the Ruhr-Universität Bochum has been studied and in part minimized. Using the E_R= 6.40 MeV narrow resonance in ¹H(¹⁵N,αγ)¹²C with an ¹⁵N energy spread of 4.55 keV, the Doppler broadening for several hydrogen-bearing gases was found to be in good agreement with expectation: e.g. for NH₃ gas a rotational-vibrational Doppler width of 10.41 ± 0.25 keV was observed (theory = 10.4 keV). Studies of the vibrational Doppler widths of H-bonds on a Si <100> surface were performed using a 4πγ-ray detection system together with UHV-chambers for sample preparation, transport, and analysis. The results showed that further improvements in the experimental set-ups are needed for such investigations.