@article{cf52bc1826af4704938de66d40d04f58,
title = "Recoil excitation of vibrational structure in the carbon 1s photoelectron spectrum of C F4",
abstract = "The carbon 1s photoelectron spectrum of C F4 measured at photon energies from 330 to 1500 eV shows significant contributions from nonsymmetric vibrational modes. These increase linearly as the photon energy increases. The excitation of these modes, which is not predicted in the usual Franck-Condon point of view, arises from the recoil momentum imparted to the carbon atom in the ionization process. A theory is presented for quantitative prediction of the recoil effect; the predictions of this theory are in agreement to the measurements. The experiments also yield the vibrational frequencies of the symmetric and asymmetric stretching modes in core-ionized C F4, the change in CF bond length upon ionization, -0.61 pm, and the Lorentzian linewidth of the carbon 1s hole, 67 meV.",
author = "Thomas, {T. Darrah} and Edwin Kukk and Rami Sankari and Hironobu Fukuzawa and Georg Pr{\"u}mper and Kiyoshi Ueda and Ralph P{\"u}ttner and James Harries and Yusuke Tamenori and Takahiro Tanaka and Masamitsu Hoshino and Hiroshi Tanaka",
note = "Funding Information: This research was carried out with the approval of JASRI (Proposal No. 2007A1046) and was supported in part by the Chemical Sciences, Geosciences and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy and by grants in aid for scientific research provided by the Japan Society for Promotion of Science (JSPS). E.K. and R.S. acknowledge financial support from the Academy of Finland and R.P. from a JSPS fellowship. Table I. Experimental conditions and results from measurements of the carbon 1 s photoelectron spectrum of C F 4 . Figures in parentheses give the statistical uncertainties. Intensities are given as a percentage of the v = 0 peak. h ν (eV) Pass energy(eV) Gaussian(meV) Lorentzian(meV) Asym. stretchIntensity (%) 330 20 42 66.0(0.3) 0.068(0.003) 350 20 44 70.2(0.4) 1.05(0.15) 375 20 47 69.0(0.4) 1.73(0.15) 400 50 75 65.7(0.4) 0.92(0.16) 600 50 90 62.0(0.6) 5.8(0.2) 800 50 106 65.5(0.5) 9.8(0.2) 1000 50 123 73.2(0.9) 14.8(0.4) 1200 50 141 87.3(0.9) 14.4(0.5) 1500 50 169 116.9(1.6) 16.4(1.0) Table II. Theoretical predictions of recoil excitation of vibrational and translational excitations in C F 4 and C H 4 upon emission of a carbon 1 s photoelectron with a kinetic energy of 1000 eV . Energies in meV. Asym. bend Asym. stretch Translation Total C F 4 HF 3.7 35.8 6.2 45.7 B3LYP 2.9 36.6 6.2 45.7 CCSD(T) 3.1 36.4 6.2 45.7 C H 4 CCSD(T) C 12 H 4 6.9 4.6 34.2 45.7 CCSD(T) C 14 H 4 5.4 3.4 30.4 39.2 CCSD(T) C 12 D 4 9.6 8.8 27.3 45.7 CCSD(T) C 12 T 4 10.5 12.4 22.8 45.7 Table III. Vibrational frequencies (meV) and equilibrium bond-length changes (pm) from theoretical calculations and experimental measurements. HF B3LYP CCSD(T) Expt Ground state h ν sym. str. 123.9 110.5 112.0 112.7 h ν asym. str. 177.8 153.8 159.8 158.8 h ν sym. bend 59.5 53.1 54.4 53.9 h ν asym. bend 85.5 76.7 78.5 78.4 Ion h ν sym. str. 125.6 111.5 109.2 119 h ν asym. str. 192.4 152.6 157.9 169 h ν sym. bend 62.5 54.4 55.0 h ν asym. bend 87.1 77.6 77.6 Δ R C F − 1.97 − 1.23 − 0.81 − 0.61 FIG. 1. Carbon 1 s photoelectron spectra of C F 4 at the photon energies indicated. For (a)–(i) the open circles represent the data, the heavy solid lines represent least-squares fits to the data using theoretical predictions of the recoil-induced vibrational excitation, and the light solid lines show the contribution from the vibrationally unexcited state. In (a) and (b), the dotted lines show the contribution from the Franck–Condon excitation of the v = 1 symmetric stretching mode. The three bottom figures, ( c ex ) , ( f ex ) , and ( i ex ) , show on an expanded scale the contributions of the major vibrational excitations to the spectra just above them. The expansion factors are shown in the upper right hand corners of these figures. FIG. 2. Ratio of v = 1 to v = 0 intensities for the asymmetric stretching mode in the carbon 1 s photoelectron spectrum of C F 4 . Plotted against the kinetic energy of the photoelectron. Open circles represent the experimental results and the lines represent the theoretical predictions. ",
year = "2008",
doi = "10.1063/1.2897756",
language = "English",
volume = "128",
journal = "Journal of Chemical Physics",
issn = "0021-9606",
publisher = "American Institute of Physics Publising LLC",
number = "14",
}