The Electric Quadrupole Moment of In^(115)

Measurements of the lines λ7852 (5s6p^1P→5s6s^1S) are λ8241 (5s6p^1P→5s5d^1D) of In II show deviations from interval rule. These deviations are satisfactorily accounted for by the presence of a nuclear electric quadrupole moment which from the first of the lines is found to be Q=0.82×10^(−24) cm^2. No trace of lines due to In^(113) was found

Evidence for a Nuclear Electric Quadrupole Moment for Sb^(123)

Measurements of the hyperfine structure of the line λ5895 of Sb II by the use of a Fabry-Perot interferometer have shown that there are deviations from the interval rule in the case of the isotope with mass number 123. The hyperfine structure intervals of the ^3D_1 level of Sb^(121) (I=5/2) are found to be 0.6801 and 0.4832 cm^(−1). The corresponding intervals in Sb^(123) (I=7/2) are 0.4814 and 0.3603 cm^(−1). The error in these measurements is of the order of 0.001 cm. The observed ratio of the two separations gives 1.407 and 1.336 for the light and heavy isotope, respectively, whereas the corresponding ratios on the basis of the interval rule are 1.400 and 1.286. The deviation in the case of the light isotope is within the experimental error. The deviation for the heavy isotope, however, is a real effect which cannot be accounted for on the basis of perturbing effects of neighboring levels and must therefore be ascribed to the presence of an electric quadrupole moment of the nucleus of Sb^(123)

Two-body effects in the decay rate of atomic levels

Recoil corrections to the atomic decay rate are considered in the order of Zm/M . The expressions are treated exactly without any expansion over Z alpha. The expressions obtained are valid both for muonic atoms (for which they contribute on the level of a few percent in high Z ions) and for electronic atoms. Explicit results for Lyman-alpha transitions for low-Z of the order (Zm/M)(Z alpha)^2 are also presented.Comment: 5 pages, 1 table, email: [email protected]

The Code Mini-Map Visualisation: Encoding Conceptual Structures Within Source Code

Modern source code editors typically include a code mini-map visualisation, which provides programmers with an overview of the currently open source code document. This paper proposes to add a layering mechanism to the code mini- map visualisation in order to provide programmers with visual answers to questions related to conceptual structures that are not manifested directly in the code. Details regarding the design and implementation of this scope information layer, which displays additional encodings that correspond to the scope chain and information related to the scope chain within a source code document, is presented. The scope information layer can be used by programmers to answer questions such as: to which scope does a specific variable belong, and in which scope is the cursor of the source code editor currently located in. Additionally, this paper presents a study that evaluates the effectiveness of adding the scope information layer to a code mini-map visualisation in order to help programmers understand scope relationships within source code. The results of the study show that the incorporating additional layers of information onto the code mini-map visualisation can have a positive effect on code understanding

The Code Mini-Map Visualisation - Encoding Conceptual Structures Within Source Code

Modern source code editors typically include a code mini-map visualisation, which provides programmers with an overview of the currently open source code document. This paper proposes to add a layering mechanism to the code mini-map visualisation in order to provide programmers with visual answers to questions related to conceptual structures that are not manifested directly in the code

Scoped: Evaluating A Composite Visualisation Of The Scope Chain Hierarchy Within Source Code

This paper presents two studies that evaluate the effectiveness of a software visualisation tool which uses a com- posite visualisation to encode the scope chain and information related to the scope chain within source code. The first study evaluates the effectiveness of adding the composite visualisation to a source code editor to help programmers understand scope relationships within source code. The second study evaluates the effectiveness of each individual component within the composite visualisation. The composite visualisation is composed of a packed circle tree diagram (overview component) and a list view (detail view component). The packed circle tree functions as an abstract mini-map to provide viewers with a high-level overview of the scope chain hierarchy within a source code document. The list view provides additional information about identifiers (variables, functions, and parameters) that are accessible from the scope within which the cursor is located, in the source code document. Both studies utilise a between-subject design, in which groups of participants were presented with source code fragments and asked to answer a series of code understanding questions. The results of the studies indicate that adding a composite visualisation to a source code editor can have a positive effect on code understanding, especially when the textual representation of the code no longer corresponds to the actual behaviour of the code (as is the case, for example, in languages such as JavaScript that implement variable hoisting)

On Using Tree Visualisation Techniques to Support Source Code Comprehension

This paper presents a design study that investigates the use of compact tree visualisations to provide software de-velopers with an overview of the static structure of a sourcecode document within a code editor in order to facilitate source code understanding and navigation. A prototype is presented which utilises an icicle tree visualisation to encode the control structure hierarchy of a source code document, as well as a circular treemap visualisation to encode the scope hierarchy of a source code document. An overview of the prototype and its functionality is given as well as a detailed discussion on the design rationale behind the tool. Possible applications and future work plans are also discussed