scholarly journals ORBITALS IN GENERAL CHEMISTRY, PART II: MATHEMATICAL REALITIES

Química Nova ◽  
2020 ◽  
Author(s):  
Guy Lamoureux ◽  
John Ogilvie
Keyword(s):  
Molecular Structure ◽  
General Chemistry ◽  
Quantum Mechanics ◽  
Constant Amplitude ◽  
Qualitative Explanation ◽  
Mathematical Functions ◽  
Atomic Orbitals ◽  
Two Factors

In Part II of a three-part series, we discuss two factors absent from textbooks of general chemistry that are important in a discussion of teaching orbitals. First, atomic orbitals are shown systematically to comprise algebraic formulae in coordinates of not one but four sets (spherical polar, paraboloidal, ellipsoidal, spheroconical coordinates). Each formula has its corresponding shape as a surface of constant amplitude; some visual examples are provided. Second, the argument that molecular structure is incompatible with quantum mechanics is presented. Despite the utility of orbitals as mathematical functions in various calculations, they are intrinsically complicated for the traditional purpose of qualitative explanation of molecular structure.

scholarly journals General Chemistry Without Orbitals

2020 ◽  
Author(s):  
Guy Lamoureux ◽  
J. F. Ogilvie
Keyword(s):  
Molecular Structure ◽  
General Chemistry ◽  
Quantum Mechanics ◽  
Hydrogen Atom

We illustrate the solutions of Schroedinger's equation for the hydrogen atom in coordinates of all four systems, and differentiate the applicability of orbitals in these four systems. We present reasons that future textbooks of general chemistry should exclude orbitals and discuss the teaching of general chemistry on this basis. The incompatibility of molecular structure and quantum mechanics is discussed before a conclusion that quantum mechanics and its orbital artifacts are irrelevant for general chemistry.

scholarly journals General Chemistry Without Orbitals

2020 ◽  
Author(s):  
Guy Lamoureux ◽  
J. F. Ogilvie
Keyword(s):  
Molecular Structure ◽  
General Chemistry ◽  
Quantum Mechanics ◽  
Hydrogen Atom

We illustrate the solutions of Schroedinger's equation for the hydrogen atom in coordinates of all four systems, and differentiate the applicability of orbitals in these four systems. We present reasons that future textbooks of general chemistry should exclude orbitals and discuss the teaching of general chemistry on this basis. The incompatibility of molecular structure and quantum mechanics is discussed before a conclusion that quantum mechanics and its orbital artifacts are irrelevant for general chemistry.

Subsequent and Subsidiary? Rethinking the Role of Applications in Establishing Quantum Mechanics

2015 ◽  
Vol 45 (5) ◽  
pp. 641-702 ◽  
Author(s):  
Jeremiah James ◽  
Christian Joas
Keyword(s):  
Molecular Structure ◽  
Quantum Mechanics ◽  
Quantum Theory ◽  
Classical Mechanics ◽  
Theory Construction ◽  
Science Pedagogy ◽  
Old Quantum Theory ◽  
The Common ◽  
Complete Quantum

As part of an attempt to establish a new understanding of the earliest applications of quantum mechanics and their importance to the overall development of quantum theory, this paper reexamines the role of research on molecular structure in the transition from the so-called old quantum theory to quantum mechanics and in the two years immediately following this shift (1926–1928). We argue on two bases against the common tendency to marginalize the contribution of these researches. First, because these applications addressed issues of longstanding interest to physicists, which they hoped, if not expected, a complete quantum theory to address, and for which they had already developed methods under the old quantum theory that would remain valid under the new mechanics. Second, because generating these applications was one of, if not the, principal means by which physicists clarified the unity, generality, and physical meaning of quantum mechanics, thereby reworking the theory into its now commonly recognized form, as well as developing an understanding of the kinds of predictions it generated and the ways in which these differed from those of the earlier classical mechanics. More broadly, we hope with this article to provide a new viewpoint on the importance of problem solving to scientific research and theory construction, one that might complement recent work on its role in science pedagogy.

QSAR models for ACE-inhibitor activity of tri-peptides based on representation of the molecular structure by graph of atomic orbitals and SMILES

2012 ◽  
Vol 23 (6) ◽  
pp. 1873-1878 ◽  
Author(s):  
A. P. Toropova ◽  
A. A. Toropov ◽  
B. F. Rasulev ◽  
E. Benfenati ◽  
G. Gini ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Ace Inhibitor ◽  
Inhibitor Activity ◽  
Atomic Orbitals ◽  
Qsar Models

scholarly journals Hybrid Atomic Orbitals in Organic Chemistry. Part 2: Critique of Practical Aspects

2019 ◽  
Author(s):  
Guy Lamoureux ◽  
J. F. Ogilvie
Keyword(s):  
Organic Chemistry ◽  
Molecular Structure ◽  
Critical Survey ◽  
Atomic Orbitals ◽  
Hybrid Orbitals

The importance of hybrid atomic orbitals, in both general and organic chemistry, is reviewed. Every contemporary textbook of organic chemistry introduces the sp3, sp2, sp model, but the suitability of these hybrid orbitals for use in the teaching of molecular structure has been increasingly questioned. Based on a critical survey of the literature, we submit seven practical criteria that deprecate the use of hybrid orbitals in a pedagogical context. We suggest how the teaching of organic chemistry without hybrid orbitals will provide students with an enhanced education.

scholarly journals 15N NMR Shifts of Eumelanin Building Blocks in Water: A Combined Quantum Mechanics/Statistical Mechanics Approach

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3616
Author(s):  
Leonardo Bruno Assis Oliveira ◽  
Tertius L. Fonseca ◽  
Benedito J. C. Cabral
Keyword(s):  
Quantum Mechanics ◽  
Statistical Mechanics ◽  
Gas Phase ◽  
Marked Effect ◽  
Complex Structure ◽  
Building Blocks ◽  
15N Nmr ◽  
Magnetic Shielding ◽  
Atomic Orbitals ◽  
Theoretical Results

Theoretical results for the magnetic shielding of protonated and unprotonated nitrogens of eumelanin building blocks including monomers, dimers, and tetramers in gas phase and water are presented. The magnetic property in water was determined by carrying out Monte Carlo statistical mechanics sampling combined with quantum mechanics calculations based on the gauge-including atomic orbitals approach. The results show that the environment polarization can have a marked effect on nitrogen magnetic shieldings, especially for the unprotonated nitrogens. Large contrasts of the oligomerization effect on magnetic shielding show a clear distinction between eumelanin building blocks in solution, which could be detected in nuclear magnetic resonance experiments. Calculations for a π-stacked structure defined by the dimer of a tetrameric building block indicate that unprotonated N atoms are significantly deshielded upon π stacking, whereas protonated N atoms are slightly shielded. The results stress the interest of NMR experiments for a better understanding of the eumelanin complex structure.

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