Experimental and theoretical study of rotationally inelastic diffraction of H_2(D_2) from methyl-terminated Si(111)
Abstract
Fundamental details concerning the interaction between H_2 and CH_3–Si(111) have been elucidated by the combination of diffractive scattering experiments and electronic structure and scattering calculations. Rotationally inelastic diffraction (RID) of H_2 and D_2 from this model hydrocarbon-decorated semiconductor interface has been confirmed for the first time via both time-of-flight and diffraction measurements, with modest j = 0 → 2 RID intensities for H_2 compared to the strong RID features observed for D_2 over a large range of kinematic scattering conditions along two high-symmetry azimuthal directions. The Debye-Waller model was applied to the thermal attenuation of diffraction peaks, allowing for precise determination of the RID probabilities by accounting for incoherent motion of the CH_3–Si(111) surface atoms. The probabilities of rotationally inelastic diffraction of H_2 and D_2 have been quantitatively evaluated as a function of beam energy and scattering angle, and have been compared with complementary electronic structure and scattering calculations to provide insight into the interaction potential between H_2 (D_2) and hence the surface charge density distribution. Specifically, a six-dimensional potential energy surface (PES), describing the electronic structure of the H_2(D_2)/CH_3−Si(111) system, has been computed based on interpolation of density functional theory energies. Quantum and classical dynamics simulations have allowed for an assessment of the accuracy of the PES, and subsequently for identification of the features of the PES that serve as classical turning points. A close scrutiny of the PES reveals the highly anisotropic character of the interaction potential at these turning points. This combination of experiment and theory provides new and important details about the interaction of H_2 with a hybrid organic-semiconductor interface, which can be used to further investigate energy flow in technologically relevant systems.
Additional Information
© 2016 AIP Publishing LLC. Received 17 June 2016; accepted 2 August 2016; published online 31 August 2016. S.J.S. acknowledges support from the Air Force Office of Scientific Research Grant No. FA9550-15-1-0428, and the Material Research Science and Engineering Center at the University of Chicago, No. NSF-DMR-14-20709. F.M., C.D., A.S.M., and M.d.C. acknowledge the MICINN Project No. FIS2013-42002-R, CAM Project No. S2014/MIT-2850, NANOFRONTMAG, and the CCC-UAM and the University of Chicago Research Computing Center for allocation of computer time. C.D. acknowledges the MICINN Project No. CTQ2013-50150-EXP and the Ramón y Cajal program. A.S.M. and M.d.C. acknowledge the FPI program of the MICINN, co-financed by the E.S.F. N.T.P. acknowledges a National Science Foundation Graduate Research Fellowship. N.S.L. acknowledges support from the National Science Foundation (Grant No. CHE-1214152), and research was in part carried out at the Molecular Materials Research Center of the Beckman Institute of the California Institute of Technology. K. J. Nihill and Z. M. Hund contributed equally to this work.Attached Files
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Additional details
- Eprint ID
- 70263
- Resolver ID
- CaltechAUTHORS:20160912-080646286
- Air Force Office of Scientific Research (AFOSR)
- FA9550-15-1-0428
- NSF
- DMR-14-20709
- Ministerio de Economía y Competitividad (MCINN)
- FIS2013-42002-R
- CAM Project
- S2014/MIT-2850
- Ministerio de Economía y Competitividad (MCINN)
- CTQ2013-50150-EXP
- Ramón y Cajal Program
- European Social Fund
- NSF Graduate Research Fellowship
- NSF
- CHE-1214152
- Created
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2016-09-12Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field