Nonbonded Bond Orders, Molecular Conformations, and Relative Stabilities of Sulfur-Nitrogen Rings and Chains

In electron-rich pi-electron systems such as the planar sulfur- nitrogen rings and chains, pi-bond orders between nonbonded atoms are often large and positive. These quantities can be used to rationalize the observed conformations of such structures and assess the relative stabilities of rings versus chains. For chains, the end-end nonbonded bond order is a convenient measure of the extra stabilization attainable on ring formation. Qualitative molecular orbital theory can be used to explain the sizes of the nonbonded bond orders and to understand trends through series of compounds

Nonbonded Bond Orders, Molecular Conformations, and Relative Stabilities of Sulfur-Nitrogen Rings and Chains

In electron-rich pi-electron systems such as the planar sulfur- nitrogen rings and chains, pi-bond orders between nonbonded atoms are often large and positive. These quantities can be used to rationalize the observed conformations of such structures and assess the relative stabilities of rings versus chains. For chains, the end-end nonbonded bond order is a convenient measure of the extra stabilization attainable on ring formation. Qualitative molecular orbital theory can be used to explain the sizes of the nonbonded bond orders and to understand trends through series of compounds

Does romantic partner support mitigate daily discrimination's association with mental health outcomes for diverse adults?

Doctor of PhilosophySchool of Family Studies and Human ServicesMajor Professor Not ListedDiscrimination is ubiquitous across the United States. Discrimination has many negative consequences for mental health, including increased anxiety, depression, and stress. Racial and ethnic minorities may experience greater discrimination, which may put them at greater risk of negative mental health consequences. Theoretically grounded in the Double ABC-X Model and Critical Race Theory, and guided by existing literature, this study tested to what extent partner support and racial/ethnic identity may moderate the associations between discrimination and mental health (e.g., depression, anxiety, and stress). Participants were collected across the United States in a sample of 698 adults involved in a romantic relationship. Data were collected via surveys collected through the Prolific survey website. Greater discrimination was significantly linked with higher depression, anxiety, and stress. More partner support was significantly associated with lower depression, anxiety, and stress. Black participants reported significantly lower depression, anxiety, and stress; whereas Hispanic participants reported significantly higher levels of depression. In most cases, race and ethnicity did not moderate the association between discrimination and mental health outcomes, but Black participants increased at steeper rates in depression and anxiety as discrimination increased, relative to other groups. Partner support was found to be a moderator between discrimination and depression, where those experiencing high levels of discrimination in the context of high partner support reported significantly lower depression than those perceiving low partner supports. Implications of how discrimination is experienced are discussed

Isospectral and Subspectral Molecules

Isospectral molecules are non-identical structures which possess the same spectrum of eigenvalues. Methods for recognizing isospectrality, procedures of Heilbronner, Herndon and .Zivkovic for constructing new isospectral mates, and the specification of the relationship among the eigenvectors of the adjacency matrix of isospectral pairs are discussed here. Instances of isospectral graphs are relatively rare. There are many cases, however, in which the spectrum of one molecular graph contains the spectrum of a second, smaller graph. In such cases, the larger, composite, graph and the smaller, component graph are said to be subspectral. Methods of McClelland, Hall and D\u27Amato for determining subspectrality of graphs are reviewed in detail. It appears that all known cases of subspectral molecules, but one, can be explained by various decomposition or factorization schemes. No chemical evidence is found so far that shows a relationship among the measured properties of isospectral or subspectral molecules. However, the existence of isospectral and subspectral molecules prevented the use of characteristic polynomial for the unique characterization of molecules in various classification schemes and in computerized chemical documentation

Study of a confined Hydrogen-like atom by the Asymptotic Iteration Method

The asymptotic iteration method (AIM) is used to obtain both special exact solutions and general approximate solutions for a Hydrogen-like atom confined in a spherical box of arbitrary radius R. Critical box radii, at which states are no longer bound, are also calculated. The results are compared with those in the literature.Comment: 10 page

On the Aromatic Stabilities of Polyacenes and Helicenes

The conjugated circuits model is used to predict the aromatic stabilities of polyacenes and helicenes. Helicenes are predicted to be always more stable than the corresponding polyacenes. This is supported by the available experimental findings

Calculation of ground- and excited-state energies of confined helium atom

We calculate the energies of ground and three low lying excited states of confined helium atom centered in an impenetrable spherical box. We perform the calculation by employing variational method with two-parameter variational forms for the correlated two-particle wave function. With just two variational parameters we get quite accurate results for both ground and excited state energies.Comment: 13 pages, No figur

Isospectral and Subspectral Molecules

Isospectral molecules are non-identical structures which possess the same spectrum of eigenvalues. Methods for recognizing isospectrality, procedures of Heilbronner, Herndon and .Zivkovic for constructing new isospectral mates, and the specification of the relationship among the eigenvectors of the adjacency matrix of isospectral pairs are discussed here. Instances of isospectral graphs are relatively rare. There are many cases, however, in which the spectrum of one molecular graph contains the spectrum of a second, smaller graph. In such cases, the larger, composite, graph and the smaller, component graph are said to be subspectral. Methods of McClelland, Hall and D\u27Amato for determining subspectrality of graphs are reviewed in detail. It appears that all known cases of subspectral molecules, but one, can be explained by various decomposition or factorization schemes. No chemical evidence is found so far that shows a relationship among the measured properties of isospectral or subspectral molecules. However, the existence of isospectral and subspectral molecules prevented the use of characteristic polynomial for the unique characterization of molecules in various classification schemes and in computerized chemical documentation

Electron correlation energy in confined two-electron systems

Radial, angular and total correlation energies are calculated for four two-electron systems with atomic numbers Z=0-3 confined within an impenetrable sphere of radius R. We report accurate results for the non-relativistic, restricted Hartree-Fock and radial limit energies over a range of confinement radii from 0.05 - 10 a0. At small R, the correlation energies approach limiting values that are independent of Z while at intermediate R, systems with Z > 1 exhibit a characteristic maximum in the correlation energy resulting from an increase in the angular correlation energy which is offset by a decrease in the radial correlation energy