Absolute cross sections and kinetic energy release distributions for electron-impact ionization and dissociation of CD<Superscript>+</Superscript><Subscript>4</Subscript>

Absolute cross sections for electron-impact dissociative excitation and ionization of CD⁺ ₄ leading to formation of ionic products (CD²⁺ ₄, CD⁺ ₃, CD⁺ ₂, CD⁺, C⁺, D⁺ ₃, D⁺ ₂, and D⁺) have been measured. The animated crossed-beams method is applied in the energy range from the reaction threshold up to 2.5 keV. Around 100 eV, the maximum cross sections are found to be (3.8±0.2) ×10^-19 cm²,  cm², (7.1±0.8) ×10^-17 cm², (9.0±0.8) × 10^-17 cm² and (3.7±0.4) ×10^-17 cm² for the heavy carbonaceous ions CD²⁺ ₄, CD⁺ ₃, CD⁺ ₂, CD⁺ and C⁺ respectively. For the light fragments, D⁺ ₃, D⁺ ₂, and D⁺, the cross sections around the maximum are found to be (5.0±0.6) ×10^-19 cm², (1.7± 0.2) ×10^-17 cm² and (10.6±1.0) ×10^-17 cm², respectively. The cross sections are presented in closed analytic forms convenient for implementation in plasma simulation codes. The analysis of ionic product velocity distributions allows determination of the kinetic energy release distributions which are seen to extend from 0 to 9 eV for heavy fragments, and up to 14 eV for light ones. The comparison of present energy thresholds and kinetic energy release with available published data gives information about states contributing to the observed processes. Individual contributions for dissociative excitation and dissociative ionization are determined for each detected product. A complete database including cross sections and energies is compiled for use in fusion application.     

Solitons for perturbed Gerdjikov–Ivanov equation in optical fibers and PCF by extended Kudryashov’s method

This paper reveals bright, dark and singular soliton solutions to the perturbed Gerdjikov–Ivanov equation by the aid of extended Kudryashov’s method. The nonlinear terms appear with full nonlinearity in order to give a generalized flavor to the model. As a byproduct of this scheme, plane waves and singular periodic solutions fall out and these solutions are listed as well.     

Low-lying dipole excitations in the stable Cd isotopes: A systematics

Low-lying dipole excitations in the medium-weight vibrational nuclei of the Cd isotopic chain were investigated by means of nuclear resonance fluorescence experiments performed at the bremsstrahlung beam of the Stuttgart Dynamitron accelerator (endpoint energy 4.1 MeV). Detailed information has been obtained on excitation energies, spins, decay widths, and transition probabilities of numerous excited states in ^{110–114,116}Cd. Additionally, the use of two Compton polarimeters enabled model-independent parity assignments for excitations in the even-even isotopes. Strongly excited J ^π = 1^? states are found in all even-even Cd nuclei at excitation energies near the sumof the energies of the first 2⁺ and 3^? states. These excitations are interpreted as the 1^? member of the quadrupole-octupole coupled quintuplet (2+?3^?). The fragmented strength observed in the odd isotopes ^111,113Cd is compared with the strength distributions in the neighboring even-even Cd isotopes.     

II. Electron-impact dissociative excitation of C<Subscript>2</Subscript>H<Stack><Subscript>2</Subscript><Superscript>+</Superscript></Stack> and C<Subscript>2</Subscript>D<Stack><Subscript>2</Subscript><Superscript>+</Superscript></Stack>

Absolute cross-sections for electron-impact dissociative ionization of C₂ H₂⁺ and C₂ D₂⁺ to CH⁺, C⁺, C₂⁺ , H⁺, CH₂⁺ and C₂D⁺ fragments are determined for electron energies ranging from the corresponding threshold to 2.5 keV. Results obtained in a crossed beams experiment are analyzed to estimate the contribution of dissociative ionization to each fragment formation. The dissociative ionization cross sections are seen to decrease for more than an order of magnitude, from CH⁺ (5.37±0.10) × 10^-17 cm² over C⁺ (4.19± 0.16) × 10^-17 cm², C₂D⁺ (3.94±0.38) × 10^-17 cm², C₂⁺ (3.82±0.15) × 10^-17 cm² and H⁺ (3.37±0.21) × 10^-17 cm² to CH₂⁺ (2.66±0.14) × 10^-18 cm². Kinetic energy release distributions of fragment ions are also determined from the analysis of the product velocity distribution. Cross section values, threshold energies and kinetic energies are compared with the data available from the literature. Conforming to the scheme used in the study of the dissociative excitation of C₂H₂⁺ ( C₂ D₂⁺ )\left( {\rm C}_2 {\rm D}_2^+ \right), the cross-sections are presented in a format suitable for their implementation in plasma simulation codes.     

Optical solitons and bifurcation analysis in fiber Bragg gratings with Lie symmetry and Kudryashov’s approach

A combination of Lie symmetry analysis and Kudryashov’s approach secures optical soliton solutions with fiber Bragg gratings. The bifurcation analysis is carried out, and the phase portrait is presented.

     

Absolute cross-sections and kinetic-energy-release distributions for electron-impact ionization and dissociation of CD<Stack><Subscript>3</Subscript><Superscript>+</Superscript></Stack>

Absolute cross-sections have been measured for electron-impact dissociative excitation and ionization of CD₂⁺ leading to formation of CD₂²⁺, CD⁺, C⁺, D₂⁺ and D⁺. The animated crossed-beams method is applied in the energy range from the reaction threshold up to 2.5 keV. The maximum total cross-sections are found to be (1.2±0.1)×10^-17 cm², (6.1±0.7)×10^-17 cm², (6.4±0.7)×10^-17 cm², (26.3±3.8)×10^-19 cm² and (14.9±1.4)×10^-17 cm² for CD₂²⁺, CD⁺, C⁺, D₂⁺ and D⁺ respectively. Individual contributions for dissociative excitation and dissociative ionization are determined for each singly-charged product, which are of significant interest in fusion plasma edge modelling and diagnostics. Conforming to the scheme recently applied in the CD₄⁺ and in the CD₃⁺ articles, the cross-sections are presented in closed analytic forms convenient for implementation in plasma simulation codes. Kinetic-energy-release distributions are determined for each ionic fragment at selected electron energies.     

Absolute cross-sections and kinetic-energy-release distributions for electron-impact ionization and dissociation of CD<Stack><Subscript>2</Subscript><Superscript>+</Superscript></Stack>

Absolute cross-sections have been measured for electron-impact dissociativeexcitation and ionization of CD ₂ ⁺ leading toformation of CD ₂ ²⁺ , CD⁺, C⁺,D ₂ ⁺ and D⁺. The animated crossed-beams methodis applied in the energy range from the reaction threshold up to 2.5 keV.The maximum total cross-sections are found to be (1.2±0.1)×10^-17 cm², (6.1±0.7)×10^-17 cm², (6.4±0.7)×10^-17 cm², (26.3±3.8)×10^-19 cm² and (14.9±1.4)×10^-17 cm² forCD ₂ ²⁺ , CD⁺, C⁺,D ₂ ⁺ and D⁺ respectively. Individualcontributions for dissociative excitation and dissociative ionization aredetermined for each singly-charged product, which are of significantinterest in fusion plasma edge modelling and diagnostics. Conforming to thescheme recently applied in the CD ₄ ⁺ and in theCD ₃ ⁺ articles, the cross-sections are presented inclosed analytic forms convenient for implementation in plasma simulationcodes. Kinetic-energy-release distributions are determined for each ionicfragment at selected electron energies.     

Solitons in nonlinear directional couplers with optical metamaterials

This paper obtains bright, dark, and singular optical solitons in nonlinear directional couplers with optical metamaterials. The mathematical principle of undetermined coefficients is applied to extract these soliton solutions, with phase-matching condition. The constraint conditions for the existence of soliton solutions naturally emerge from the solutions. Both twin-core couplers and multiple-core couplers are studied in this paper.

     

Optical soliton perturbation for Gerdjikov–Ivanov equation via two analytical techniques

This paper employs two integration procedures to obtain soliton solutions to the perturbed Gerdjikov–Ivanov equation. They are G′/G²–expansion method and the sine–cosine method. Bright, dark and singular solitons are revealed along with a few of the combo–soliton solutions. The existence criteria of these solitons are also given.