The spin-coupled (SC) theory of molecular electronic structure is introduced as the modern development of classical valence bond (VB) theory. Various important aspects of the SC wave function are described. Attention is particularly focused on the construction and properties of different sets of N-electron spin function in different spin bases, such as the Kotani, Rumer and Serber. Applications of the SC description to a range of different kinds of chemical problems are presented, beginning with simple examples: the H2 and CH4 molecules. This is followed by the description offered by the SC wave function of more complex situations such as the insertion reaction of H2 into CH2(1A1), the phenomenon of hypervalence as displayed by molecules such as diazomethane, CH2N2, SF6 and XeF2. The SC description of the ground and excited states of benzene is briefly surveyed. This is followed by the SC description of antiaromatic systems such as C4H4 and related molecules.

/pdf/modern-valence-bond-theory-2oa0z08ns8.pdf

Modern valence bond theory

Cross sections and rate coefficients are provided for inelastic collision processes of electrons and protons with CxHy and CxHy+ (x=2,3; 1⩽y⩽2x+2) hydrocarbon species in a wide range of collision energies and plasma (gas) temperatures The considered processes include electron-impact ionization and dissociation of CxHy, dissociative excitation, ionization and recombination of CxHy+ with electrons, and both charge transfer and atom exchange in proton channels are considered separately The presented cross sections are based upon a critical assessment of available experimental data and upon an extensive use of a number of semi-empirical, physically well grounded cross section scaling relationships Information is also provided for the energetics of each individual reaction channel The cross sections and rate coefficients are presented in compact analytic forms

Collision processes of C2,3Hy and C2,3Hy+ hydrocarbons with electrons and protons

The critical fusion reactor design issue of tritium codeposition in tokamaks with carbon as wall material is closely linked with the plasma chemistry involving hydrocarbons. A complete set of cross sections for all important electron- and proton-impact processes with CHy (y=1–4) hydrocarbon impurities and their ions CHy+ is presented. The cross sections are derived on the basis of most recent experimental information and well established cross section scaling relationships. The cross sections are presented in closed analytic forms convenient for implementation in plasma simulation codes.

/pdf/collision-processes-of-chy-and-chy-hydrocarbons-with-plasma-8hjwab674w.pdf

Collision processes of CHy and CHy+ hydrocarbons with plasma electrons and protons

Research on the neutralization of ion beams by electron-capture collisions with atomic particles has largely been within the domain of atomic and high-energy physics with the emphasis on understanding the fundamentals of ion-atom interactions. This account presented a chemist's perception of the possibilities to obtain new information about molecules formed by neutralization of beams of molecular ions. Only reactions in which a molecule is formed in an electron-capture process are discussed. In this article neutralized ion beam spectroscopy was defined as a technique for investigating modes of energy disposal in species formed when a fast beam of ions is neutralized in the electron-transfer reaction AB/sup +/ + M(g) ..-->.. AB* + M*/sup +/ where AB/sup +/ is any diatomic or polyatomic ion and M is a thermalized target atom. The target atom series M = Cs, K, Na, Ca, Mg, and Zn that covers an ionization potential range of 3.9 to 9.4 eV. The most significant technical advance from neutralized ion beam studies is the capability of producing beams of stable or metastable molecules that would be difficult, if not impossible, to obtain by other methods. 5 figures, 2 tables. (DP)

Neutralized ion-beam spectroscopy

This chapter contains sections titled: Introduction Classical Valence Bond Theory The Spin-coupled Valence Bond Theory Survey of Results of Spin-coupled Valence Bond Theory Calculation of Matrix Elements of the Hamiltonian Recent Developments in Valence Bond Theory Intermolecular Forces Conclusions 

Modern Valence Bond Theory

Ab initio calculations have been performed for states of C${\mathrm{H}}^{+}$ which arise from atomic ${\mathrm{C}}^{+}(^{2}P)$ and $\mathrm{H}(^{2}S)\ensuremath{-}X^{1}\ensuremath{\Sigma}^{+}$, $A^{1}\ensuremath{\Pi}$, $^{3}\ensuremath{\Pi}$, and $^{3}\ensuremath{\Sigma}^{+}$. Potential curves have been constructed over a wide range of internuclear distances. All computed energies are believed to be within 1 eV of their exact nonrelativistic Born-Oppenheimer value, and all energy differences are believed to have an accuracy of better than 0.3 eV. Results, with known experimental values in parentheses, are ${R}_{e}(X^{1}\ensuremath{\Sigma}^{+})=2.136$ (2.137) a.u.; ${D}_{e}^{0}(X^{1}\ensuremath{\Sigma}^{+})=4.11$ (4.21) eV; ${R}_{e}(A^{1}\ensuremath{\Pi})=2.232$ (2.333) a.u.; ${T}_{e}(X\ensuremath{-}A)=24970$ (24146) ${\mathrm{cm}}^{\ensuremath{-}1}$; ${R}_{e}(^{3}\ensuremath{\Pi})=2.130$ a.u. No evidence is found for a quasibound $^{3}\ensuremath{\Sigma}^{+}$ Rydberg state, although such behavior has been predicted for isoelectronic BH.

Calculated Potential-Energy Curves for CH +

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Sheldon Green

Author Tools

Chat about Author

Papers

Calculated Potential-Energy Curves for CH +