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SUMMARY:Quantum State-Resolved Studies of Methane/Surface Scattering  by V
 ibrational Spectroscopy
DTSTART:20260326T170000
DTEND:20260326T183000
DTSTAMP:20261002T020931Z
UID:e27dcaaebac4be722e43d380ad44534c68294b6468fe7f184b3a9ede
CATEGORIES:Conferences - Seminars
DESCRIPTION:Rainer Beck\nMethane dissociation is the rate limiting step in
  the steam reforming process used by the chemical industry to convert natu
 ral gas into a mixture of H2 and CO known as synthesis gas. To better unde
 rstand the microscopic mechanism and reaction dynamics of methane chemisor
 ption\, we use vibrational spectroscopies and infrared lasers for quantum 
 state-resolved studies of methane dissociation and state-to-state scatteri
 ng on Ni and Pt surfaces [1]. Our experiments prepare surface incident met
 hane molecules in specific ro-vibrational quantum states by state-selectiv
 e infrared laser excitation in a molecular beam. The state prepared molecu
 les then collide with a clean single crystal transition metal surface in u
 ltrahigh vacuum and both reactive and non-reactive processes are monitored
  by infrared spectroscopic techniques.\nSurface bound methyl species as pr
 oducts of the dissociative chemisorption of methane are detected by Reflec
 tion Absorption Infrared Spectroscopy (RAIRS). RAIRS allows for real-time 
 and in-situ monitoring of the uptake of chemisorbed methyl species enablin
 g quantum state-resolved measurements of reactive sticking coefficients. R
 AIRS is also used to study the vibrationally bond selective dissociation o
 f partially deuterated methane demonstrating that a single quantum of C-H 
 stretch excitation is sufficient to achieve bond-selective chemisorption. 
 Furthermore\, RAIRS allows for site specific detection of reaction product
 s used to measure separately the dissociation probability of methane on st
 eps and terraces sites on Pt(211) [2-3].\nNon-reactive\, inelastic energy 
 transfer is probed by combining infrared laser tagging of scattered molecu
 les with bolometric detection. These first methane state-to-state scatteri
 ng experiments yield state-resolved information about rotational and vibra
 tional energy transfer between the incident molecule and the solid surface
  [4]. Furthermore\, for scattering from a reactive surface\, we observe ev
 idence for surface-induced vibrational energy redistribution (SIVR) in the
  scattered molecules\, the extend of which is related to the catalytical a
 ctivity of the target surface. [5-7]. For methane scattering from the iner
 t Au(111) surface\, we are able to detect\, for the first time to our know
 ledge\, conservation of wavefunction reflection parity in molecule-surface
  scattering [8] which is a uniquely quantum mechanical effect.\n\nReferenc
 es\n[1] H.J. Chadwick and R.D. Beck\, Chem. Soc. Rev. 2016\, 45\, 3576-359
 4.\n[2] H.J. Chadwick\, H. Guo\, A. Gutiérrez Gonzáles\; J.P. Menzel\, B
 . Jackson\, R.D. Beck\, J. Chem. Phys. 2018\, 148\, 1470.\n[3] A. Gutiérr
 ez Gonzáles. F.F. Crim\, R.D. Beck\, J. Chem. Phys. 2018\, 149\, 74701.\n
 [4] J. Werdecker\, M.E. van Reijzen\, B.J. Chen\, R.D. Beck\, Phys. Rev. L
 ett. 2018\, 120\, 53402.\n[5] J. Werdecker\, J. Werdecker\, B.-J. Chen\, M
 .E. van Reijzen\, A. Farjamina\, B. Jackson\, R.D. Beck\, Phys. Rev. Res. 
 2020\, 2\, 43251.\n[6] P. Floß\, C.S. Reilly\, D.J. Auerbach\, R.D. Beck\
 , Frontiers in Chemistry 2023\, 11\, 88.\n[7] C.S. Reilly\, P. Floß\, B-J
 . Chen\, D.J. Auerbach\, R.D. Beck\, J. Chem. Phys. 2023\, 158 21.\n[8] C.
  Reilly et al.\, Science 387\, 962–967 (2025).\n 
LOCATION:CE 1 5 https://plan.epfl.ch/?room==CE%201%205 https://epfl.zoom.u
 s/j/67032521917?pwd=XUgWogWHi1nn3yIg42cVcFQB0CO3rF.1
STATUS:CONFIRMED
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