Measuring surface phonons using molecular spin-echo. Issue 23 (1st June 2022)

• Record Type: Journal Article
• Authors: Chadwick, Helen; Alexandrowicz, Gil
• Is Part Of: Physical chemistry chemical physics. Volume 24:Issue 23(2022)
• Page Start: 14198
• Page End: 14208
• Publication Date: 2022-06-01
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/d2cp01372j
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : A new method to measure surface phonons with a molecular beam is presented. Abstract : A new method to measure surface phonons with a molecular beam is presented. The method extends the principles of 3 He spin-echo spectroscopy, to the more complex case of a molecular beam exchanging energy with the surface. Measurements are presented for inelastic scattering of D2 from a Cu(111) surface. Similarly to helium spin-echo, experiments can be performed along optimal tilted projections making it possible to resolve energy peaks with a high energy resolution which is not restricted by the spread of energies of the incident beam. Two analysis methods for these molecular spin echo experiments are presented. A classical approach, analogous to that used for helium spin-echo, explains the most dominant excitation peaks measured, whereas a semi-classical approach allows us to identify smaller peaks which are related to the complexity of the multiple spin-rotation states which exist for molecules.