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Analytic Threads - Annual Newsletters 2014-2020, Messiah University

Educator Scholarship & Departmental Newsletters

Faculty and student updates. Analytic Threads is the annual newsletter of the Department of Computing, Mathematics and Physics at Messiah University. It is sent annually to alumni and is also available electronically at the website messiah.edu/cmp

Quantum Mechanics & Its Broader Implications: The Von Neumann– Wigner Interpretation, Aeowyn Kendall

Computing, Mathematics and Physics Student Scholarship

Essay for PHYS 402 Quantum Mechanics

Like the popular Copenhagen Interpretation, the von Neumann-Wigner Interpretation of quantum mechanics posits that measurement causes a collapse of the wavefunction. Once observed, the wavefunction collapses from a superposition of various states to just one of the possibilities. While the Copenhagen Interpretation does not identify what constitutes a measurement, an observer, or an observation, the von Neumann-Wigner Interpretation specifies that consciousness is necessary for the measurement process to occur (we might say a reading of the measurement), and that it is consciousness itself that causes wavefunction collapse. In simple terms, the von Neumann-Wigner Interpretation …

Full Correlation In A Multiconfigurational Study Of Bimetallic Clusters : Restricted Active Space Pair-Density Functional Theory Study Of [2fe-2s] Systems, Samuel J. Stoneburner, Davide Presti, Donald G. Truhlar, Laura Gagliardi

Educator Scholarship

Iron-sulfur clusters play a variety of important roles in protein chemistry, and understanding the energetics of their spin ladders is an important part of understanding these roles. Computational modeling can offer considerable insight into such problems; however, calculations performed thus far on systems with multiple transition metals have typically either been restricted to a single-configuration representation of the density, as in Kohn-Sham theory, or been limited to correlating excitations only within an active space, as in active-space self-consistent field methods. For greater reliability, a calculation should include full correlation, i.e., not only correlation internal to the active space but also …

Beyond Density Functional Theory: The Multiconfigurational Approach To Model Heterogeneous Catalysis, Samuel J. Stoneburner, Carlo Alberto Gaggioli, Christopher J. Cramer, Laura Gagliardi

Educator Scholarship

Catalytic processes are crucially important for many practical chemical applications. Heterogeneous catalysts are especially appealing because of their high stability and the relative ease with which they may be recovered and reused. Computational modeling can play an important role in the design of more catalytically active materials through the identification of reaction mechanisms and the opportunity to assess hypothetical catalysts in silico prior to experimental verification. Kohn-Sham density functional theory (KS-DFT) is the most used method in computational catalysis because it is affordable and it gives results of reasonable accuracy in many instances. Furthermore, it can be employed in a …

Growth And Characterization Of Znse Thin Films By Rf Magnetron Co-Sputtering, Hallie Miller

Honors Projects and Presentations: Undergraduate

Zinc-selenide, ZnSe,is aII-IV semiconductor that is known for its wide band gap of ~2.6 eV. In the growing world of advanced electronics, ZnSe thin films are useful to study in order to widen our understanding of semiconductor physics and to enable us to create and develop higher preforming electronics. In this study, we have grown ZnSe thin films by radio frequency (RF) magnetron sputtering. We are specifically seeking to understand how the ratio of Zinc to Selenium,and the temperature the films are grown at, affects the band gap and crystalline structure. Ten different ratios of Zn to Se were grown, …

Features Of The Structure, Development, And Activity Of The Zebrafish Noradrenergic System Explored In New Crispr Transgenic Lines, Matthew J. Farrar, Kristine E. Kolkman, Joseph R. Fetcho

Educator Scholarship & Departmental Newsletters

The noradrenergic (NA) system of vertebrates is implicated in learning, memory, arousal, and neuroinflammatory responses, but is difficult to access experimentally. Small and optically transparent, larval zebrafish offer the prospect of exploration of NA structure and function in an intact animal. We made multiple transgenic zebrafish lines using the CRISPR/Cas9 system to insert fluorescent reporters upstream of slc6a2, the norepinephrine transporter gene. These lines faithfully express reporters in NA cell populations, including the locus coeruleus (LC), which contains only about 14 total neurons. We used the lines in combination with two‐photon microscopy to explore the structure and projections of the …

Mc-Pdft Can Calculate Singlet-Triplet Splittings Of Organic Diradicals., Samuel J. Stoneburner, Donald G. Truhlar, Laura Gagliardi

Educator Scholarship

The singlet-triplet splittings of a set of diradical organic molecules are calculated using multiconfiguration pair-density functional theory (MC-PDFT) and the results are compared with those obtained by Kohn-Sham density functional theory (KS-DFT) and complete active space second-order perturbation theory (CASPT2) calculations. We found that MC-PDFT, even with small and systematically defined active spaces, is competitive in accuracy with CASPT2, and it yields results with greater accuracy and precision than Kohn-Sham DFT with the same parent functional. MC-PDFT also avoids the challenges associated with spin contamination in KS-DFT. It is also shown that MC-PDFT is much less computationally expensive than CASPT2 …

Search For T Violation In Charm Meson Decays, Abaz Kryemadhi

Educator Scholarship & Departmental Newsletters

Using data from the FOCUS (E831) experiment, we have searched for T violation in charm meson decays using the four-body decay channels D0→K−K+π−π+, D+→KS0K+π−π+, and Ds+→KS0K+π−π+. The T violation asymmetry is obtained using triple-product correlations and assuming the validity of the CPT theorem. We find the asymmetry values to be ATviol(D0)=0.010±0.057(stat.)±0.037(syst.), ATviol(D+)=0.023±0.062(stat.)±0.022(syst.), and ATviol(Ds+)=−0.036±0.067(stat.)±0.023(syst.). Each measurement is consistent with no T violation. New measurements of the CP asymmetries for some of these decay modes are also presented.

Study Of Λc+ Cabibbo Favored Decays Containing A Λ Baryon In The Final State, Abaz Kryemadhi

Educator Scholarship & Departmental Newsletters

Using data from the FOCUS experiment (FNAL–E831), we study the decay of Λc+ baryons into final states containing a Λ hyperon. The branching fractions of Λc+ into Λπ+, Λπ+π+π− and ΛK¯0K+ relative to that into pK−π+ are measured to be 0.217±0.013±0.020, 0.508±0.024±0.024 and 0.142±0.018±0.022, respectively. We also report new measurements of Γ(Λc+→Σ0π+)Γ(Λc+→Λπ+)=1.09±0.11±0.19, Γ(Λc+→Σ0π+π+π−)Γ(Λc+→Λπ+π+π−)=0.26±0.06±0.09 and Γ(Λc+→Ξ(1690)0(ΛK¯0)K+)Γ(Λc+→ΛK¯0K+)=0.32±0.10±0.04. Further, an analysis of the subresonant structure for the Λc+→Λπ+π+π− decay mode is presented.

Measurement Of The Branching Ratio Of The Decay D0→Π−Μ+Ν Relative To D0→K−Μ+Ν, Abaz Kryemadhi

Educator Scholarship & Departmental Newsletters

We present a new measurement of the branching ratio of the Cabibbo suppressed decay D0→π−μ+ν relative to the Cabibbo favored decay D0→K−μ+ν and an improved measurement of the ratio |f+π(0)/f+K(0)|. Our results are 0.074±0.008±0.007 for the branching ratio and 0.85±0.04±0.04±0.01 for the form factor ratio, respectively.

Study Of The Cabibbo-Suppressed Decay Modes D0→Π−Π+ And D0→K−K+, Abaz Kryemadhi

Educator Scholarship & Departmental Newsletters

Using data from the FOCUS (E831) experiment at Fermilab, we present a new measurement for the branching ratios of the Cabibbo-suppressed decay modes D0→π−π+ and D0→K−K+. We measured: Γ(D0→K−K+)/Γ(D0→π−π+)=2.81±0.10(stat)±0.06(syst), Γ(D0→K−K+)/Γ(D0→K−π+)=0.0993±0.0014(stat)±0.0014(syst), and Γ(D0→π−π+)/Γ(D0→K−π+)=0.0353±0.0012(stat)±0.0006(syst). These values have been combined with other experimental data to extract the ratios of isospin amplitudes and the phase shifts for the D→KK and D→ππ decay channels.

Effect Of Chemical Sputtering On The Growth And Structural Evolution Of Magnetron Sputtered Cnx Thin Films, Niklas Hellgren, Mats P.J Jõesaar, Esteban Broitman, Per Sandström, Lars Hultman, Jan-Eric Sundgren

Educator Scholarship & Departmental Newsletters

The growth and microstructure evolution of carbon nitride CN_x (0≤x≤0.35) films, deposited by reactive d.c. magnetron sputtering in Ar/N₂ discharges has been studied. The substrate temperature T_S varied between 100 and 550°C, and the N₂ fraction in the discharge gas varied from 0 to 100%. It is found that the deposition rate and film morphology show strong dependence on T_S and nitrogen fraction. For growth temperature of 100°C, the films are amorphous, and essentially unaffected by the nitrogen fraction. For T_S>200°C, however, the nitrogen fraction has more significant effect on the growth and …

Nanoindentation And Strain Characteristics Of Nanostructured Boride/Nitride Films, Niklas Hellgren, R A. Andrievskii, G V. Kalinnikov, P Sandstrom, D V. Shtanskii

Educator Scholarship & Departmental Newsletters

The hardness, elastic modulus, and elastic recovery of nanostructured boride/nitride films 1–2 µm thick have been investigated by the nanoindentation technique under the maximum loads over a wide range (from 5 to 100 mN). It is demonstrated that only the hardness parameters remain constant at small loads (5–30 mN). The data obtained are discussed and compared with the parameters determined by other methods.

Nitrogen 1s Electron Binding Energy Assignment In Carbon Nitride Thin Films With Different Structures, Niklas Hellgren, Wei Tao Zheng, Ke Zhao Xing, Michael Lögdlund, Åsa A. Johansson, U Gelivs, William R. Salaneck, Jan Eric Sundgren

Educator Scholarship & Departmental Newsletters

Carbon nitride thin films deposited by dc unbalanced magnetron sputtering have been analyzed by high-resolution X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The XPS data show that N 1s binding states depend on substrate temperature (T_s). By comparison with the Raman spectra, N 1s binding states are assigned in which nitrogen atoms are mainly bound to sp² and sp³ carbon atoms at T_s = 100°C, whereas at T_s = 500°C nitrogen atoms are mainly bonded to sp², sp³ and sp¹ carbon atoms.