The Experts below are selected from a list of 207 Experts worldwide ranked by ideXlab platform
Adam P. Hitchcock - One of the best experts on this subject based on the ideXlab platform.
-
Influence of Local Environment on Inner Shell Excitation Spectra, Studied by Electron and X-ray Spectroscopy and Spectromicroscopy
Zeitschrift für Physikalische Chemie, 2017Co-Authors: Adam P. HitchcockAbstract:Abstract Inner Shell Excitation spectroscopy is a local probe of the unoccupied electronic structure in the immediate vicinity of the core excited atom. As such, one might expect the Inner Shell spectrum of a given unit (a molecular fragment or a repeat unit of a solid) to be largely independent of where that unit is located. This is often an implicit assumption in spectral analysis and analytical applications. However, there are situations where Inner Shell Excitation spectra exhibit significant sensitivity to their local environment. Here I categorize the ways in which Inner Shell spectra are affected by their local environment, and give examples from a career dedicated to developing a better understanding of Inner Shell Excitation spectroscopy, its experimental techniques, and applications.
-
Inner-Shell Excitation spectroscopy of peroxides
Chemical Physics, 2015Co-Authors: K. L. Harding, G Cooper, Adam P. Hitchcock, Samanbir Kalirai, R. Hayes, Michael ThompsonAbstract:O 1s Inner-Shell Excitation spectra of a number of vapor phase molecules containing peroxide bonds - hydrogen peroxide (H2O2), di-t-butylperoxide ((BuOBu)-Bu-t-Bu-t), benzoyl peroxide, ((C6H5(CO)O)(2)), luperox-F [1,3(4)-bis(tertbutylperoxyisopropyl)benzene], and analogous, non-peroxide compounds - water, t-butanol and benzoic acid have been measured. C 1s spectra are also reported. O 1s spectra of solid benzoic acid, di-t-butylperoxide and luperox-F recorded using a scanning transmission X-ray microscope, are also reported, and compared to the corresponding gaseous spectra. Spectral interpretation was aided by comparing the spectra of the peroxide and non-peroxide counterparts and with ab initio calculations. A characteristic O 1s -> sigma(O-O)* transition at 533.0(3) eV is identified in each peroxide species, which is absent in the corresponding non-peroxide counterpart species. The energy and intensity of the 533 eV peroxide feature is stable and thus useful for analysis of peroxides in mixtures, such as tracking residual peroxide initiators, or peroxides produced in fuel cells. (C) 2015 Elsevier B.V. All rights reserved.
-
Inner Shell Excitation spectroscopy of biphenyl and substituted biphenyls: probing ring-ring delocalization.
The journal of physical chemistry. A, 2005Co-Authors: Jian Wang, David Tulumello, G Cooper, Adam P. HitchcockAbstract:Quantitative optical oscillator strength spectra for C 1s Excitation and ionization of gas-phase biphenyl, decafluorobiphenyl, and 2,2′-bis(bromomethyl)-1,1′-biphenyl have been derived from electron energy loss spectroscopy recorded under electric dipole dominated conditions. The C 1s X-ray absorption spectrum of hexaphenylbenzene has been recorded in the solid state. The C 1s spectral features are interpreted with the aid of ab initio calculations for core Excitation of benzene, biphenyl, hexafluorobenzene, and decafluorobiphenyl. A weak feature at 287.7 eV in biphenyl is identified a saC1 sf ﷿*deloc transition, characteristic of ring -ring delocalization. Its intensity and position are shown to be related to the average torsion angle and thus the extent of ﷿-﷿-interaction between adjacent aromatic rings. The effects of perfluoro substitution on core Excitation spectra are also characterized and discussed.
-
Inner-Shell Excitation spectroscopy and X-ray photoemission electron microscopy of adhesion promoters.
Journal of Physical Chemistry B, 2005Co-Authors: David Tulumello, I. Koprinarov, E. G. Rightor, G. E. Mitchell, Steve Rozeveld, Greg Meyers, G Cooper, Adam P. Hitchcock, Ted M. StokichAbstract:The C 1s, Si 2p, Si 2s, and O 1s Inner-Shell Excitation spectra of vinyltriethoxysilane, trimethylethoxysilane, and vinyltriacetoxysilane have been recorded by electron energy loss spectroscopy under scattering conditions dominated by electric dipole transitions. The spectra are converted to absolute optical oscillator strength scales and interpreted with the aid of ab initio calculations of the Inner-Shell Excitation spectra of model compounds. Electron energy loss spectra recorded in a transmission electron microscope on partly cured adhesion promoter, atomic force micrographs, and images and X-ray absorption spectra from X-ray photoemission electron microscopy of as-spun and cured vinyltriacetoxysilane-based adhesion promoter films on silicon are presented. The use of these measurements in assisting chemistry studies of adhesion promoters for electronics applications is discussed.
-
Inner Shell Excitation of glycine, glycyl-glycine, alanine and phenylalanine
Journal of Electron Spectroscopy and Related Phenomena, 2004Co-Authors: G Cooper, David Tulumello, Michelle L. Gordon, Cássia Curan Turci, Konstantine Kaznatcheev, Adam P. HitchcockAbstract:Abstract Oscillator strengths for C 1s Excitation spectra of gaseous glycine (Gly), alanine (Ala), phenylalanine (Phe) and glycyl-glycine (Gly-Gly), plus the N 1s and O 1s spectra of Gly and Gly-Gly, have been derived from Inner Shell electron energy-loss spectroscopy recorded under scattering conditions where electric dipole transitions dominate (2.5 keV residual energy, θ:∼2°). X-ray absorption spectra of solid glycine and glycyl-glycine were recorded in a scanning transmission X-ray microscope. Complications in solid state measurements associated with sample crystallinity and the benefits of spectroscopy in a microscope to resolve them are illustrated. Inner Shell Excitation spectral features characteristic of the peptide bond, readily identified by comparison of the spectra of glycine and glycyl-glycine, include: a ∼0.3 eV shift of the C 1 s → π C O ∗ peak, and introduction of a new pre-edge feature in the N 1s spectrum. These effects are due to 1 s → π amide ∗ transitions introduced with formation of the peptide bond. The concept of spectral additivity (building block model) is tested by a comparison of the C 1s spectrum of phenylalanine with those of benzene and alanine.
Nobuo Ueno - One of the best experts on this subject based on the ideXlab platform.
-
Ion Desorption by Inner-Shell Excitation and Photodegradation of Poly(vinylidene fluoride)
MRS Online Proceedings Library, 2011Co-Authors: K. Okudaira Koji, Eiichi Kobayashi, Satoshi Kera, Kazuhiko Mase, Nobuo UenoAbstract:Auger electron spectra (AES) and Auger electron photo-ion coincidence (AEPICO) spectra of poly(vinlylidene fluoride) (PVDF) were observed to study the mechanism of effective fluorine ion (F^+) desorption by irradiation of photons corresponding to the transition from F 1s to s(C-F). In the AES at photon energy (hυ) = 690.3 eV (from F1s to |σ|(C-F)), the spectator-Auger shift is about 3 eV. At hn = 690.3 eV the contribution of spectator Auger electron to the observed Auger spectrum is large. In the F^+ AEPICO spectra at hυ = 690.3 eV an intense peak appears. The peak positions of the F^+ AEPICO spectra are in agreement with those of the Auger spectra. These results indicate that the mechanism for effective F^+ ion desorption induced by the transition from F1s to σ(C-F) occurs through the spectator-Auger processes. The efficiency of ion desorption depends on the electronic structure of the spectator-Auger final state.
-
surface photodegradation of poly vinylidene fluoride by Inner Shell Excitation
Surface Review and Letters, 2006Co-Authors: Koji K Okudaira, Satoshi Kera, Eiichi Kobayashi, Kazuhiko Mase, Nobuo UenoAbstract:Poly(vinylidene fluoride) (PVDF, –(CH2–CF2)n–) shows the effective H+ desorption induced by the irradiation of photon corresponding to the transition from carbon (C) 1s to σ(C–H)*. In order to clarify the effect of the C–H bond scission by the irradiation, near-edge X-ray absorption fine structure (NEXAFS) spectra and the kinetic energy (Ek) distribution of desorbed ion were observed. By the irradiation of photon near C 1s region, a new peak appears in the C 1s NEXAFS spectra at photon energy of 285 eV, which is about 3 eV lower than that of the lowest peak in the NEXAFS spectrum of the pristine PVDF film. The appearance of the lowest NEXAFS peak of irradiated PVDF film is assigned to the transition to π*. It indicates that the irradiation of photons near C 1s region introduces carbon–carbon double bonds into the backbone chain of PVDF. At early stage of X-ray exposure the yield of desorbed ion with low Ek (~ 2 eV) decreases rapidly. The ion with low Ek is assigned to H+ desorbed from the sp3-hybrid state, which is characteristics of the pristine PVDF. It indicates that formation of double bonds in PVDF backbone chain makes the number of sp3-hybrid state decrease. This variation occurs by irradiation of photons corresponding to the transition from C 1s to σ(C–H)* more rapidly than that to the transition to σ(C–F)*.
-
study of excited states of fluorinated copper phthalocyanine by Inner Shell Excitation
Journal of Electron Spectroscopy and Related Phenomena, 2004Co-Authors: Koji K Okudaira, Satoshi Kera, Kazuhiko Mase, Hiroyuki Setoyama, H Yagi, Antoine Kahn, Nobuo UenoAbstract:Abstract Near edge X-ray absorption fine structure (NEXAFS) spectra of hexadecafluoro copper phthalocyanine (FCuPc) films (thickness of 50 A) on MoS 2 substrates were observed near the carbon (C) and fluorine (F) K-edges. From the analysis of the dependence of C and F K-edge NEXAFS spectra on the photon incidence angle ( α ), the average molecular tilt angle was determined to be 30°. The lowest and second lowest peaks in the F K-edge NEXAFS were assigned to the transition to σ ∗ . In the ion time-of-flight mass spectra of FCuPc excited by photons near the F K-edge, F + , CF + , and CF 3 + ions were mainly observed. These results indicate that CC bonds as well as CF bonds are broken by the photon irradiation. From the analysis of the partial ion yield spectra of F + and CF + near the F K-edge, the lowest and second lowest peaks in the F K-edge NEXAFS spectra could be assigned to transitions to σ(CF) ∗ and σ(CC) ∗ , respectively.
-
excited states of perfluorinated oligo p phenylene by Inner Shell Excitation
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2003Co-Authors: Koji K Okudaira, Kazuhiko Mase, K Ohara, Hiroyuki Setoyama, Toshiyasu Suzuki, Y Sakamoto, Motoyasu Imamura, S Hasegawa, Nobuo UenoAbstract:Abstract Ion time-of-flight (TOF) mass spectra and near-edge X-ray absorption fine structure (NEXAFS) spectra of perfluorinated oligo( p -phenylene) (PF-8P) films near fluorine (F) and carbon (C) K-edges were observed. In ion TOF mass spectra near F and C K-edges, F + , CF + and CF 3 + were intensely observed. It indicates that C–C bonds of phenyl ring as well as C–F bonds are broken by irradiation of photons near F and C K-edges. Partial ion yield (PIY) spectra of PF-8P show clear hν dependence near F and C K-edges. Especially, near F K-edge, the PIY spectra of F + increases remarkably at hν =689.2 eV, which corresponds to the lowest peak in NEXAFS. The lowest peak in the NEXAFS near fluorine K-edge is assigned to the transition from F1s to σ (C–F) * . Furthermore, from the analysis of PIY spectra of PF-8P near carbon K-edge, the peak at hν =289.5 eV is ascribed to the transition from C1s to σ (C–F) * .
-
Site-Specific Chemical-Bond Scission in Poly(Methyl Methacrylate) by Inner Shell Excitation
1997Co-Authors: Nobuo Ueno, Kenichiro TanakaAbstract:The results of photon-stimulated ion desorption (PSID) from thin solid films of poly(methyl methacrylate) (PMMA) and corresponding polymers, poly(methyl acrylate) (PMA) and poly(methacrylic acid) (PMAA), owing to Inner-Shell Excitation, are briefly reviewed. The results show that an enhancement of PSID takes place effectively upon electron Excitation to a particular antibonding molecular orbital, indicating that the Excitation to the antibonding state plays a major role in PSID enhancement. As a typical example, CH 3 + desorption via oxygen Is electron Excitation was shown as a function of photon energy. By comparison of the photon energy dependences of PSID yields of CH 3 + from the three polymers, it was found that the Excitation of oxygen 1s electron at OCH 3 to the σ * state localized at COCH 3 in PMMA results in the enhanced emission of CH 3 + by bond scission at the side chain (O-CH 3 ), not at the main chain. The results indicate that there is a strong correlation between the sites of Excitation and the following chemical-bond rupture. It is pointed out that monochromatic synchrotron radiation can be used as a scalpel to cut a chemical bond selectively in a molecular solid.
Shuntaro Watanabe - One of the best experts on this subject based on the ideXlab platform.
-
Femtosecond lattice relaxation induced by Inner-Shell Excitation
Journal of the Optical Society of America B, 2002Co-Authors: Taro Sekikawa, Tomohiro Yamazaki, Y. Nabekawa, Shuntaro WatanabeAbstract:The ultrafast relaxation dynamics of the Inner-Shell Excitation in a CsCl crystal were investigated, for the first time to our knowledge, by use of the high harmonics of a femtosecond Ti:sapphire laser. The luminescence due to the recombination between the valence electron and the Inner-Shell hole evolved with a time constant of 220±50 fs, corresponding to the lattice-displacement time for the self-trapping of the Inner-Shell hole. This is the first observation of the lattice relaxation induced by the Inner-Shell Excitation on the femtosecond time scale. The dynamics of the Inner-Shell hole are discussed by use of a configuration-coordinate model for the Inner-Shell hole.
-
Femtosecond lattice relaxation induced by Inner-Shell Excitation
Technical Digest. Summaries of papers presented at the Conference on Lasers and Electro-Optics. Postconference Technical Digest (IEEE Cat. No.01CH3717, 2001Co-Authors: Taro Sekikawa, Tomohiro Yamazaki, Y. Nabekawa, Shuntaro WatanabeAbstract:Summary form only given. We demonstrate the first application of high harmonics (HH) of a femtosecond Ti:sapphire laser to the femtosecond time-resolved luminescence spectroscopy of Inner-Shell Excitation in an alkali-halide crystal CsCl. HH are shown to be the useful light source for the research on Inner-Shell excited states by observing the femtosecond luminescence induced by Inner-Shell Excitation. The time dependence of the luminescence by Inner-Shell Excitation reflects the relaxation dynamics of Inner-Shell excited states and clarifies the relaxation processes related to Inner-Shell excited states.
-
Femtosecond Time-Resolved Luminescence Spectroscopy of Inner-Shell Excitation by HighOrder Harmonics
Ultrafast Phenomena XII, 2001Co-Authors: Taro Sekikawa, Tomohiro Yamazaki, Y. Nabekawa, Satoshi Miura, Shuntaro WatanabeAbstract:High-order harmonics of a Ti:sapphire laser were applied to femtosecond luminescence spectroscopy for the observation of the relaxation dynamics of Inner-Shell Excitation in an alkali-halide crystal for the first time.
Satoshi Kera - One of the best experts on this subject based on the ideXlab platform.
-
Ion Desorption by Inner-Shell Excitation and Photodegradation of Poly(vinylidene fluoride)
MRS Online Proceedings Library, 2011Co-Authors: K. Okudaira Koji, Eiichi Kobayashi, Satoshi Kera, Kazuhiko Mase, Nobuo UenoAbstract:Auger electron spectra (AES) and Auger electron photo-ion coincidence (AEPICO) spectra of poly(vinlylidene fluoride) (PVDF) were observed to study the mechanism of effective fluorine ion (F^+) desorption by irradiation of photons corresponding to the transition from F 1s to s(C-F). In the AES at photon energy (hυ) = 690.3 eV (from F1s to |σ|(C-F)), the spectator-Auger shift is about 3 eV. At hn = 690.3 eV the contribution of spectator Auger electron to the observed Auger spectrum is large. In the F^+ AEPICO spectra at hυ = 690.3 eV an intense peak appears. The peak positions of the F^+ AEPICO spectra are in agreement with those of the Auger spectra. These results indicate that the mechanism for effective F^+ ion desorption induced by the transition from F1s to σ(C-F) occurs through the spectator-Auger processes. The efficiency of ion desorption depends on the electronic structure of the spectator-Auger final state.
-
high resolution Inner Shell Excitation spectroscopy of h2 phthalocyanine
Journal of Chemical Physics, 2006Co-Authors: Satoshi Kera, M B Casu, A Scholl, Th Schmidt, D R Batchelor, E Ruhl, E UmbachAbstract:We report on a combined experimental and theoretical carbon and nitrogen K-edge near-edge x-ray absorption fine structure investigation on condensed metal-free phthalocyanine (H2Pc). Based on the results from improved virtual orbital calculations, all resonances in the experimental high-resolution data can be assigned to various electronic transitions. The comparison between experiments and calculations further shows that a significant influence of the core hole, which affects both the transition energies and the cross sections, is present and must be considered in theoretical approaches. Moreover, additional fine structure is clearly resolved for the first N 1s→π* transition, which can be interpreted as vibronic coupling to the electronic core Excitation.
-
surface photodegradation of poly vinylidene fluoride by Inner Shell Excitation
Surface Review and Letters, 2006Co-Authors: Koji K Okudaira, Satoshi Kera, Eiichi Kobayashi, Kazuhiko Mase, Nobuo UenoAbstract:Poly(vinylidene fluoride) (PVDF, –(CH2–CF2)n–) shows the effective H+ desorption induced by the irradiation of photon corresponding to the transition from carbon (C) 1s to σ(C–H)*. In order to clarify the effect of the C–H bond scission by the irradiation, near-edge X-ray absorption fine structure (NEXAFS) spectra and the kinetic energy (Ek) distribution of desorbed ion were observed. By the irradiation of photon near C 1s region, a new peak appears in the C 1s NEXAFS spectra at photon energy of 285 eV, which is about 3 eV lower than that of the lowest peak in the NEXAFS spectrum of the pristine PVDF film. The appearance of the lowest NEXAFS peak of irradiated PVDF film is assigned to the transition to π*. It indicates that the irradiation of photons near C 1s region introduces carbon–carbon double bonds into the backbone chain of PVDF. At early stage of X-ray exposure the yield of desorbed ion with low Ek (~ 2 eV) decreases rapidly. The ion with low Ek is assigned to H+ desorbed from the sp3-hybrid state, which is characteristics of the pristine PVDF. It indicates that formation of double bonds in PVDF backbone chain makes the number of sp3-hybrid state decrease. This variation occurs by irradiation of photons corresponding to the transition from C 1s to σ(C–H)* more rapidly than that to the transition to σ(C–F)*.
-
study of excited states of fluorinated copper phthalocyanine by Inner Shell Excitation
Journal of Electron Spectroscopy and Related Phenomena, 2004Co-Authors: Koji K Okudaira, Satoshi Kera, Kazuhiko Mase, Hiroyuki Setoyama, H Yagi, Antoine Kahn, Nobuo UenoAbstract:Abstract Near edge X-ray absorption fine structure (NEXAFS) spectra of hexadecafluoro copper phthalocyanine (FCuPc) films (thickness of 50 A) on MoS 2 substrates were observed near the carbon (C) and fluorine (F) K-edges. From the analysis of the dependence of C and F K-edge NEXAFS spectra on the photon incidence angle ( α ), the average molecular tilt angle was determined to be 30°. The lowest and second lowest peaks in the F K-edge NEXAFS were assigned to the transition to σ ∗ . In the ion time-of-flight mass spectra of FCuPc excited by photons near the F K-edge, F + , CF + , and CF 3 + ions were mainly observed. These results indicate that CC bonds as well as CF bonds are broken by the photon irradiation. From the analysis of the partial ion yield spectra of F + and CF + near the F K-edge, the lowest and second lowest peaks in the F K-edge NEXAFS spectra could be assigned to transitions to σ(CF) ∗ and σ(CC) ∗ , respectively.
A P Hitchcock - One of the best experts on this subject based on the ideXlab platform.
-
Inner Shell Excitation of gas phase carbonates and α γ dicarbonyl compounds
Chemical Physics, 2007Co-Authors: Robert Lessard, G Cooper, Jerome Cuny, A P HitchcockAbstract:Abstract The Inner-Shell (C 1s, N 1s, O 1s) Excitation spectra of dimethoxymethanone, diphenoxymethanone, and a series of α,γ-dicarbonyl compounds – 2,4-pentanedione, N-acetylacetamide, malonamide, acetyl anhydride, dimethyl malonate, diethyl malonate, 2-imidodicarbonic diamide, di-t-butyl iminodicarboxylate and dimethyldicarbonate – have been recorded in the gas phase with Inner Shell electron energy loss spectroscopy in the scattering regime dominated by electric dipole transitions. All spectra are presented on absolute oscillator strength intensity scales. They are interpreted with the aid of chemical series systematics and with the help of ab initio calculations. As found in a recent study of the X-ray absorption spectra of condensed carbonyl compounds [S.G. Urquhart, H. Ade, J. Phys. Chem. B 106 (2002) 8531], there is a very systematic correlation of the C 1 s → π C O ∗ transition energy and the relative oxidation at the carbonyl carbon, as expressed by a suitable oxidation index such as the sum of the atomic numbers or Pauling electronegativities of the elements bonded to the carbonyl carbon. Although the calculations clearly show there is delocalization between the two carbonyl groups, this had no detectible influence on the Inner Shell spectra. The absence of signals associated with π∗ delocalization is explained in terms of core hole localization and symmetry effects.
-
Inner Shell Excitation spectroscopy of the peptide bond comparison of the c 1s n 1s and o 1s spectra of glycine glycyl glycine and glycyl glycyl glycine
Journal of Physical Chemistry A, 2003Co-Authors: Michelle L. Gordon, G Cooper, Cássia Curan Turci, Konstantine Kaznatcheev, C Morin, Tohru Araki, A P HitchcockAbstract:Oscillator strengths for C 1s, N 1s, and O 1s Excitation spectra of gaseous glycine and the dipeptide, glycyl−glycine, have been derived from Inner-Shell electron energy-loss spectroscopy recorded under scattering conditions where electric dipole transitions dominate (2.5 keV residual energy, θ ≈ 2°). X-ray absorption spectra of solid glycine, glycyl−glycine, glycyl−glycyl−glycine, and a large protein, fibrinogen, were recorded in a scanning transmission X-ray microscope. The experimental spectra are assigned through interspecies comparisons and by comparison to ab initio computed spectra of various conformations of glycine and glycyl−glycine. Inner-Shell Excitation spectral features characteristic of the peptide bond are readily identified by comparison of the spectra of gas-phase glycine and glycyl−glycine. They include a clear broadening and a ∼0.3 eV shift of the C 1s → π*CO peak and introduction of a new pre-edge feature in the N 1s spectrum. These effects are due to 1s → π*amide transitions introduc...
-
Inner Shell Excitation spectroscopy of molecules using inelastic electron scattering
Journal of Electron Spectroscopy and Related Phenomena, 2000Co-Authors: A P HitchcockAbstract:Abstract Instrumentation and recent applications of Inner-Shell electron energy loss spectroscopy of gas phase molecules are reviewed. An overview of recent work in an historical perspective is provided. Comparison is made to the complementary technique of X-ray absorption spectroscopy. Highlights are described of recent applications in: polymer analogue studies, in situ studies of transient species, non-dipole spectroscopy, and systematic measurements of generalized oscillator strengths.
-
Inner Shell Excitation spectroscopy of transient molecules: HBS, HBO, and H3B3O3
The Journal of Chemical Physics, 1999Co-Authors: L. E. Ennis, A P HitchcockAbstract:Inner Shell electron energy spectroscopy (ISEELS) was used to study HBS, HBO, and H3B3O3, reactive, transient species generated in situ. The reaction of H2S with crystalline boron in a quartz tube was used to produce thioborine (HBS) at ∼1100 °C, and borine (HBO) at ∼1200 °C. The reaction of H2O vapor with crystalline boron in a quartz tube at ∼1200 °C was used to produce boroxine (H3B3O3). These species were identified from their Inner Shell Excitation spectra and mass spectrometry. The B 1s, S 2s, and S 2p ISEEL spectra of HBS, and the B 1s and O 1s spectra of HBO and H3B3O3 are reported and analyzed with the help of GSCF3 ab initio calculations. A reaction scheme is proposed for the generation of HBO from the reaction of H2S and boron in a heated quartz tube.
-
Inner Shell Excitation of pf3 pcl3 pcl2cf3 opf3 and spf3 part i spectroscopy
Principles and Practice of Constraint Programming, 1998Co-Authors: John J Neville, Nobuhiro Kosugi, Ronald G. Cavell, Astrid Jurgensen, A P HitchcockAbstract:Abstract Total ion yield spectra of PF 3 , PCl 3 , PCl 2 CF 3 , OPF 3 and SPF 3 were recorded in the region of P 2p, P 2s, S 2p, S 2s and halogen (Cl 2p, F 1s) Excitation using synchrotron radiation. The P 2p spectra are interpreted with GSCF3 ab initio configuration interaction calculations optimized for core Excitation studies. The experimental–theoretical comparison is based on both absolute intensities (oscillator strengths) and transition energies. The calculations indicate that several of the discrete states (e.g., that in PF 3 at 136.5 eV) are best described as LS-coupled states because the core–valence electron exchange is very large and thus the singlet–triplet splitting is larger than the spin–orbit splitting. While the state at 136.5 eV in PF 3 is particularly notable, analogous P 2p excited states with large singlet–triplet splittings are calculated in PCl 3 , PCl 2 CF 3 , OPF 3 and SPF 3 . Aspects of partial ion yield measurements (particularly the PF 3 + yield of PF 3 and the SPF 3 + yield of SPF 3 ) support this interpretation by revealing isolated single states without a corresponding partner at the spin–orbit splitting. The partial ion yields help clarify spectral interpretation by removing interference from overlap with adjacent states having the normal ( j , j )-coupled ion core character.