Development of Full-Strength Elastic Element Section with Open Shell

We report a theoretical investigation and elucidation of the x-ray absorption spectra of neutral benzene and of the benzene cation. The generation of the cation by multiphoton ultraviolet (UV) ionization as well as the measurement of the carbon K-edge spectra of both species using a table-top high-harmonic generation (HHG) source are described in the companion experimental paper [M. Epshtein et al., J. Phys. Chem. A., submitted. Available on ChemRxiv]. We show that the 1sC -> pi transition serves as a sensitive signature of the transient cation formation, as it occurs outside of the spectral window of the parent neutral species. Moreover, the presence of the unpaired (spectator) electron in the pi-subshell of the cation and the high symmetry of the system result in significant differences relative to neutral benzene in the spectral features associated with the 1sC ->pi* transitions. High-level calculations using equation-of-motion coupled-cluster theory provide the interpretation of the experimental spectra and insight into the electronic structure of benzene and its cation. The prominent split structure of the 1sC -> pi* band of the cation is attributed to the interplay between the coupling of the core -> pi* excitation with the unpaired electron in the pi-subshell and the Jahn-Teller distortion. The calculations attribute most of the splitting (~1-1.2 eV) to the spin coupling, which is visible already at the Franck-Condon structure, and estimate the additional splitting due to structural relaxation to be around ~0.1-0.2 eV. These results suggest that x-ray absorption with increased resolution might be able to disentangle electronic and structural aspects of the Jahn-Teller effect in benzene cation.

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Room Temperature Alkali Metal Reduction of Carbon Dioxide

10.26434/chemrxiv.12665336 ◽

2020 ◽

Author(s):

Lucas A. Freeman ◽

Akachukwu D. Obi ◽

Haleigh R. Machost ◽

Andrew Molino ◽

Asa W. Nichols ◽

...

Keyword(s):

Alkali Metal ◽

Alkali Metals ◽

Room Temperature ◽

Chemical Reduction ◽

Bond Cleavage ◽

Open Shell ◽

Metal Reduction ◽

One Pot ◽

Earth Abundant ◽

Electron Reduction

The reduction of the relatively inert carbon–oxygen bonds of CO2 to access useful CO2-derived organic products is one of the most important fundamental challenges in synthetic chemistry. Facilitating this bond-cleavage using earth-abundant, non-toxic main group elements (MGEs) is especially arduous because of the difficulty in achieving strong inner-sphere interactions between CO2 and the MGE. Herein we report the first successful chemical reduction of CO2 at room temperature by alkali metals, promoted by a cyclic(alkyl)(amino) carbene (CAAC). One-electron reduction of CAAC-CO2 adduct (1) with lithium, sodium or potassium metal yields stable monoanionic radicals clusters [M(CAAC–CO2)]n(M = Li, Na, K, 2-4) and two-electron alkali metal reduction affords open-shell, dianionic clusters of the general formula [M2(CAAC–CO2)]n (5-8). It is notable that these crystalline clusters of reduced CO2 may also be isolated via the “one-pot” reaction of free CO2 with free CAAC followed by the addition of alkali metals – a reductive process which does not occur in the absence of carbene. Each of the products 2-8 were investigated using a combination of experimental and theoretical methods.

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Form Factor of an Open-Shell Atom

Optics and Spectroscopy ◽

10.1134/1.1131504 ◽

2000 ◽

Vol 89 (1) ◽

pp. 4

Author(s):

A. N. Khoperskiı̆

Keyword(s):

Form Factor ◽

Open Shell

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Open shell CNDO treatments on small inorganic radicals

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19733067 ◽

1973 ◽

Vol 38 (10) ◽

pp. 3067-3073 ◽

Cited By ~ 16

Author(s):

P. Čársky ◽

M. Macháček ◽

R. Zahradník

Keyword(s):

Open Shell

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Elektronenspektren der open-shell-Systeme

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19740812 ◽

1974 ◽

Vol 39 (3) ◽

pp. 812-820 ◽

Cited By ~ 2

Author(s):

R. Stösser ◽

P. Janietz ◽

J. Sauer ◽

C. Jung

Keyword(s):

Open Shell

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‘She Sleeps Well and Eats an Egg’

10.1093/oso/9780198779025.003.0003 ◽

2018 ◽

Author(s):

Hannah Newton

Keyword(s):

Life Style ◽

The Body ◽

Serious Illness ◽

Second Stage ◽

Full Strength ◽

Central Argument

Serious illness often left the body weak and lean, full of the ‘footsteps of disease’; it wasn’t until full strength and flesh had returned that the patient was pronounced back to health. This chapter explores the second stage of recovery in contemporary perceptions, the restoration of strength, or ‘convalescence’. It asks how the patient’s growing strength was measured and promoted, and unveils a concept of convalescent care, ‘analeptics’. The central argument is that both the mechanisms and the measures for the restoration of strength were intimately connected to the ‘non-natural things’, six dietary and life-style factors. The opening sections explain why the body was weak after illness, and categorize the convalescent within contemporary schemes of health. The rest of the chapter is structured around the signs of increasing strength, each of which was associated with a particular non-natural: ‘the final purge’, ‘sleeping through the night’, ‘feeling hungry’, ‘growing cheerful’, and ‘sitting up to going abroad’.

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Transalkylierung und protonenkatalysierte C-C-Spaltung bei n-Butyl-und n-Pentylbenzol in der Gasphase / Transalkylation and Proton Catalyzed C-C-Cleavage of Gaseous n-Butyl and w-Pentyl Benzenes

Zeitschrift für Naturforschung B ◽

10.1515/znb-1979-0325 ◽

1979 ◽

Vol 34 (3) ◽

pp. 495-501 ◽

Cited By ~ 19

Author(s):

C. Wesdemiotis ◽

H. Schwarz ◽

C. C. Van de Sande ◽

F. Van Gaever

Keyword(s):

Hydrogen Exchange ◽

Closed Shell ◽

Open Shell ◽

Molecular Ions ◽

Exchange Reactions ◽

Intramolecular Exchange ◽

Carbon Carbon Bond ◽

Exchange Processes ◽

Reaction Channels ◽

Alkyl Benzenes

Abstract The investigation of several 13carbon and deuterium labelled n-butyl and n-pentyl benzenes demonstrate that chemical ionization (reagent gas: methane) induces specific carbon-carbon bond cleavages of the alkyl group. The extent of competing reaction channels as for instance direct alkene elimination versus dealkylation/reprotonation is analyzed. Partial hydrogen exchange processes between reagent ions and substrate molecules are restricted to the phenyl ring. Intramolecular exchange reactions between the side chain and the aromatic ring which are typical for the open shell molecular ions of alkyl benzenes are not observed for analogous closed shell cations.

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Linear-Scaling Open-Shell MP2 Approach: Algorithm, Benchmarks, and Large-Scale Applications

Journal of Chemical Theory and Computation ◽

10.1021/acs.jctc.1c00093 ◽

2021 ◽

Author(s):

P. Bernát Szabó ◽

József Csóka ◽

Mihály Kállay ◽

Péter R. Nagy

Keyword(s):

Large Scale ◽

Open Shell ◽

Linear Scaling

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