Isotopic Labelling in Vibrational Spectroscopy: A Technique to Decipher the Structure of Surface Species

Lagunov, Oleg; Drenchеv, Nikola; Chakarova, Kristina; Panayotov, D.; Hadjiivanov, Konstantin

doi:10.1007/s11244-017-0833-x

Cited by 9 publications

(5 citation statements)

References 61 publications

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“…Figure shows the comparison of the nonlabeled and isotopically substituted acetophenone at multilayer coverages obtained at 115 K. As expected, the major shifts were observed for the vibrational bands at 1683 and 1276 cm –1 , with both of them being related to the chemical bonds involving the 13 C atom. The vibrational band at 1683 cm –1 related to the CO stretching vibration shifts downward by 36 cm –1 upon isotopic labeling, agreeing with the shift of about 38 cm –1 estimated in the scope of simple harmonic approximation . The vibrational band at 1276 cm –1 related to the “x-sensitive” mode is red-shifted by 26 cm –1 for the labeled compound.…”

Section: Resultssupporting

confidence: 84%

“…The vibrational band at 1683 cm −1 related to the CO stretching vibration shifts downward by 36 cm −1 upon isotopic labeling, agreeing with the shift of about 38 cm −1 estimated in the scope of simple harmonic approximation. 22 The vibrational band at 1276 cm −1 related to the "x-sensitive" mode is red-shifted by 26 cm −1 for the labeled compound. The latter red-shift is in a good agreement with isotopic shift factor expected for exchange of 12 C 12 C to 13 C 12 C of 24 cm −1 .…”

Section: ■ Experimental Sectionmentioning

confidence: 95%

“…To further support the assignments of the bands, the multilayer spectrum of acetophenone isotopically labeled with 13 C-carbonyl was additionally acquired by IRAS. The resulting spectra were then compared with the spectra of the nonlabeled compound in the scope of the harmonic approximation …”

Section: Methodsmentioning

confidence: 99%

“…The resulting spectra were then compared with the spectra of the nonlabeled compound in the scope of the harmonic approximation. 22 ■ RESULTS AND DISCUSSION Assignment of Vibrational Bands Based on the Multilayer Spectra and Theoretical Calculations. Adsorption of acetophenone was investigated on well-defined Pt(111) surface under ultrahigh-vacuum conditions in the temperature range 115−185 K by combination of IRAS and molecular beam techniques at sub-and multilayer coverages.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Coverage-Dependent Adsorption Geometry of Acetophenone on Pt(111)

Attia

Schauermann

2019

J. Phys. Chem. C

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A microscopic-level understanding of the interaction of hydrocarbons with transition metal surfaces is an important prerequisite for rational design of new materials with improved catalytic properties. Particularly, their adsorption geometry might critically affect the ability of the surface to activate the selected chemical bonds. In this study, we investigate the interaction of a simple carbonyl compound acetophenone with Pt(111) single crystalline surface as a prototypical system. We apply a combination of molecular beam techniques with infrared reflection−absorption spectroscopy (IRAS) to address the adsorption geometry of acetophenone in a broad coverage range. In particular, we compare the IR spectra recorded for multilayer coverages, reflecting the molecular structure of largely unperturbed molecules, with the spectra obtained at submonolayer coverages, at which the molecular structure of acetophenone is perturbed by the interaction with the underlying metal. The acquired spectroscopic information suggests that two types of acetophenone surface species are formed and coexist on the surface at low temperature. At low coverages, the species S1 are populated, which adopt a flat-lying adsorption geometry with the benzene ring lying parallel to the surface plane. With increasing acetophenone coverage, a second type of the surface species appearsthe species S2exhibiting a more upright orientation with the benzene ring tilted away from the surface. The latter species are more weakly bound to the underlying metal substrate as compared to the flat-lying species S1 as indicated by the temperature dependence of their population on the surface. Additionally, we report a detailed assignment of the vibrational bands in acetophenone based on the comparison of the unperturbed molecular species accumulated in a multilayer with the spectra of gaseous acetophenone theoretically computed with the MP2/aug-cc-pVQZ-level of theory.

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Section: Resultssupporting

confidence: 84%

Section: ■ Experimental Sectionmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 99%

Section: ■ Experimental Sectionmentioning

confidence: 99%

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Coverage-Dependent Adsorption Geometry of Acetophenone on Pt(111)

Attia

Schauermann

2019

J. Phys. Chem. C

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“…The environment of Cu species on fresh and used samples of zeolites NaYCu5x and 13X-CuI has been studied also performing CO adsorption in combination with FTIR spectroscopy at temperature lower than room temperature, specifically at 105 K. At this temperature, the CO adsorbance patterns show in fact a higher amount of peaks compared to the ones obtained at 323 K as next to Cu species the zeolite framework itself and additional Na + species contribute to CO adsorption [65,66]. Fig.…”

Section: Deactivation Of Cu-fau Zeolitesmentioning

confidence: 99%