Search results for "Electron affinity"
showing 10 items of 42 documents
Thin film growth and band lineup of In2O3 on the layered semiconductor InSe
1999
Thin films of the transparent conducting oxide In2O3 have been prepared in ultrahigh vacuum by reactive evaporation of indium. X-ray diffraction, optical, and electrical measurements were used to characterize properties of films deposited on transparent insulating mica substrates under variation of the oxygen pressure. Photoelectron spectroscopy was used to investigate in situ the interface formation between In2O3 and the layered semiconductor InSe. For thick In2O3 films a work function of φ = 4.3 eV and a surface Fermi level position of EF−EV = 3.0 eV is determined, giving an ionization potential IP = 7.3 eV and an electron affinity χ = 3.7 eV. The interface exhibits a type I band alignmen…
Calculations on solvents and co-solvents of single-wall carbon nanotubes: Cyclopyranoses
2005
Abstract (10,10) single-wall carbon nanotube (SWNT) presents consistency between relatively small solubility, and great partition coefficients and kinetic stability. Solubility of SWNTs is investigated in a variety of solvents, finding a class of non-hydrogen-bonding Lewis bases that provides good solubility. Electron affinity of d -glucopyranoses ( d -Glcpn) suggests colloids of negatively charged SWNTs in water.
Observation of multiply charged silver-cluster anions
2001
Singly charged silver-cluster anions are produced in a laser vaporization source and transferred into a Penning trap. After size selection the clusters are subjected to an electron bath in the trap, which results in the attachment of further electrons. The relative abundance of dianions or trianions as a function of the clusters' size is analyzed by time-of-flight mass spectrometry. Silver-cluster dianions are observed for sizes n≥ 24 and trianions for n > 100. In addition, a detailed study of the cluster sizes 24 ?n? 60 shows a pronounced resistance to electron attachment for singly charged anions Agn- with a closed electronic shell, in particular Ag29-, Ag33-, and Ag39-. Both the threshol…
Synthesis and investigation of charge transport properties in adducts of hole transporting carbazole derivatives and push-pull azobenzenes
2019
Abstract In order to investigate the viability of a material design for bulk heterojunction (BHJ) organic solar cells, where hole transporting group is bound to the donor moiety, we report the synthesis and charge transport characteristics of 3-(diphenylamino)carbazolyl-functionalized derivatives of 2-(4-((4-(dimethylamino)phenyl)diazenyl)benzylidene)-1H-indene-1,3-dione (DMAAzi) chromophore. Three different bounding configurations were examined in these adducts. Additionally, a trityl-functionalized derivative of DMAAzi was prepared and used for comparison purposes. All of the synthesized materials form thin amorphous films from volatile organic solvents and exhibit glass transition temper…
Oligo(phenylenevinylene)s with increased electron affinity: 1,3,4-oxadiazoles in the main chain
2001
Stilbenoid chromophores and 2,5-diaryl-1,3,4-oxadiazoles are compounds with wide technical importance. Their intense fluorescence is used in szintillators and optical whiteners and their semiconducting properties makes them valuable emissive or electron conducting layers in organic light emitting diodes (OLED). The synthesis and the electronic spectra of soluble oligo(phenylenevinylene)s with 1,3,4-oxadiazoles in the main chain are presented. The Huisgen reaction of tetrazole-terminated stilbenoid compounds with aromatic acyl chlorides yields model compounds, isophthalic acid dichlorides lead to soluble polymers with well-defined conjugated segments, as can be seen in the electronic spectra…
On the theoretical determination of the electron affinity of ozone
1993
Multiconfigurational electron correlation methods have been analyzed in order to theoretically compute the electron affinity (EA) of ozone. The near-degeneracy correlation effects, which are so important in O3 and O 3 − , have been described using complete active space (CAS) SCF wave functions. Remaining dynamic correlation effects are computed using second-order perturbation theory (the CASPT2 method). The best calculated adiabatic value (including zero-point energy corrections), 2.19 eV, is about 0.09 eV larger than the experimental value. Comparative studies using size-consistent coupled pair functional approaches (CPF and ACPF) have also been performed. The harmonic frequencies in O 3 −…
Laser photodetachment of radioactive $^{128}$I$^−$
2017
International audience; The first experimental investigation of the electron affinity (EA) of a radioactive isotope has been conducted at the CERN-ISOLDE radioactive ion beam facility. The EA of the radioactive iodine isotope (128)I (t (1/2) = 25 min) was determined to be 3.059 052(38) eV. The experiment was conducted using the newly developed Gothenburg ANion Detector for Affinity measurements by Laser PHotodetachment (GANDALPH) apparatus, connected to a CERN-ISOLDE experimental beamline. (128)I was produced in fission induced by 1.4 GeV protons striking a thorium/tantalum foil target and then extracted as singly charged negative ions at a beam energy of 20 keV. Laser photodetachment of th…
Reducing the contribution of the photoemission process to the unwanted beam in photoelectron sources at accelerators
2017
Negative electron affinity (NEA) GaAs photocathodes show different pulse responses depending on the wavelength of photoexcitation. The pulse response at 800 nm shows a long and relatively intense tail, whereas at 400 nm, a tail of similar shape but with an intensity lower by around two orders of magnitude is observed. We explain this behavior with the specific properties of NEA photocathodes and compare it with the response of a positive electron affinity photocathode.
PNO-CI and CEPA studies of electron correlation effects
1974
Ab initio calculations of the potential curves of low laying electronic states of OH are performed on the basis of a variational configuration interaction wavefunction (PNO-CI) and the coupled electron pair approximation (CEPA). The latter approach yields a ground state potential curve which deviates from the RKR curve by less than 200 cm−1 in the region from 0.7 to 1.6 A. Calculated ground state constants are as follows (experimental values in parentheses): r e = 0.972 (0.971) A, B e = 18.85 (18.87) cm−1, α e = 0.727 (0.714) cm−1, ω e = 3742 (3739) cm−1, ω e χ e = 85.3 (86.4) cm−1, μ0 = 1.686 (1.66) D, D e = 4.35 (4.63) eV,IP = 12.78 (13.36?) eV, El.Aff. = 1.51 (1.83) eV, v 00(2Π↔2Σ+) = 32…
The electron affinity of phosphorus
2007
We have measured the energies of all three fine structure components in the 3PJ ground state of the negative ion of phosphorus using laser photodetachment threshold spectroscopy. The experiment yielded an electron affinity of 746.68(6) meV. The ΔJ = 2–0, 2–1 and 1–0 fine structure splittings were determined to be 32.73(7) meV, 22.48(7) meV and 10.25(3) meV, respectively. In the experiment, a mass selected beam of P− ions was merged with the output from a pulsed infrared optical parametric oscillator. The residual atoms produced in the photodetachment process were detected and used as a monitor of the photon-energy dependence of the relative cross section. The Wigner law was fitted to each o…