Ab initio molecular dynamics and quantum dynamics calculations on reactive scattering of methane from metal surfaces.
Event details
| Date | 10.12.2015 |
| Hour | 14:00 › 15:00 |
| Speaker |
Prof. Geert-Jan Kroes Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, The Netherlands |
| Location | |
| Category | Conferences - Seminars |
The dissociative chemisorption of methane on Ni surfaces represents a rate limiting step of the steam reforming reaction, the current commercial process for H2 production. The practical importance of this process has led to much research on reactive scattering of methane from metal surfaces, and theory is now challenged through the availability of a wide range of quantum-state-resolved data [1, 2]. Being able to interpret and reproduce this data through calculations will ultimately enable better theoretical predictions of heterogeneously catalyzed processes [3]. It has recently become possible to compute statistically accurate reaction probabilities for methane reacting on metal surfaces through ab initio molecular dynamics (AIMD) calculations. Comparison with experiment for CHD3 + Pt(111) shows that AIMD can already predict reaction probabilities with an accuracy of 2-3 kcal/mol with an off-the-shelve, standard density functional [4]. AIMD and quantum dynamics (QD) calculations also reveal details of the dynamics, such as whether the molecule has to rotate or move along the surface on the way to the barrier to make reaction possible [4]. Thereby the calculations also yield insights in the validity of dynamical approximations, which will be useful to achieving highly accurate QD calculations in future. Recent QD calculations on the effect of the initial rotational state of CHD3 on Pt(111) predict a large effect on reaction of the orientation of the principal axis of this molecule. In order to react initially non-rotating molecules have to enter through a "reactive gate" of orientations of the CD3 umbrella axis, which then reorients to react. These results may aid the interpretation of experiments on the effect of rotational alignment of CHD3 on Ni(100) [1]. Finally, we have used a semi-empirical approach to density functional theory to achieve quantitative agreement with experiments on dissociative chemisorption of CHD3 on Ni(111).
References.
[1] B. L. Yoder, R. Bisson, and R. D. Beck, Science 329, 553 (2010).
[2] D. R. Killelea, V. L. Campbell, N. S. Shuman, and A. L. Utz, Science 319, 790 (2008).
[3] G. J. Kroes, J.Phys.Chem.Lett. 6, 4106 (2015).
[4] F. Nattino, H. Ueta, H. Chadwick, M. E. van Reijzen, R. D. Beck, B. Jackson, M. C. van Hemert, and G. J. Kroes, J.Phys.Chem.Lett. 5, 1294 (2014).
References.
[1] B. L. Yoder, R. Bisson, and R. D. Beck, Science 329, 553 (2010).
[2] D. R. Killelea, V. L. Campbell, N. S. Shuman, and A. L. Utz, Science 319, 790 (2008).
[3] G. J. Kroes, J.Phys.Chem.Lett. 6, 4106 (2015).
[4] F. Nattino, H. Ueta, H. Chadwick, M. E. van Reijzen, R. D. Beck, B. Jackson, M. C. van Hemert, and G. J. Kroes, J.Phys.Chem.Lett. 5, 1294 (2014).
Practical information
- Informed public
- Free
Organizer
- Prof. Rainer Beck