Classical representation for hydrogen atom in s-states

2019 ◽  
Vol 6 (2) ◽  
pp. 225-233 ◽  
Author(s):  
Tasko P. Grozdanov ◽  
Evgeni A. Solov’ev
Keyword(s):  
Hydrogen Atom ◽  
Classical Representation ◽  
S States

Excitation of the 21S and 23S states of helium atoms by electron and hydrogen atom impact

1977 ◽  
Vol 55 (5) ◽  
pp. 396-402 ◽  
Author(s):  
Madeleine M. Felden ◽  
Marceau A. Felden
Keyword(s):  
Hydrogen Atom ◽  
Cross Sections ◽  
Ground State ◽  
Wave Functions ◽  
The Other ◽  
Helium Atoms ◽  
Atomic Wave ◽  
Excitation Cross Sections ◽  
The One ◽  
S States

Ochkur's approximation is used to analyse the excitation of 21S and 23S levels of helium atoms from the ground state by electron and hydrogen atom impact. Calculations are made with different atomic wave functions. To characterize the 11S and 21S states we use, on the one hand, the wave functions of Byron and Joachain, on the other hand, those of Hylleraas and Marriott and Seaton. For the 11S and 23S states, calculations are made firstly with the wave functions of Byron and Joachain and Morse, Young, and Haurwitz, secondly with those of Shull and Lödwin. Numerical values are tabulated and compared in each case. The discrepancies show the importance of the choice of atomic wave functions in the calculation of the excitation cross sections. Available experimental data and corresponding theoretical values obtained from other theories are plotted and compared with the present results.

Measurement of the Lamb shift in the hydrogen atom

1982 ◽  
Vol 138 (10) ◽  
pp. 347 ◽  
Author(s):  
Yurii L. Sokolov ◽  
V.P. Yakovlev
Keyword(s):  
Hydrogen Atom ◽  
Lamb Shift

Direct Cyclization of Alkenyl Thioester via Transition Metal‐hydrogen Atom Transfer/radical‐polar Crossover Mechanism

2019 ◽  
Author(s):  
Shiori Date ◽  
Kensei Hamasaki ◽  
Karen Sunagawa ◽  
Hiroki Koyama ◽  
Chikayoshi Sebe ◽  
...  
Keyword(s):  
Natural Products ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Synthetic Method ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Hydride Hydrogen ◽  
Sulfur Heterocycles ◽  
One Step

<div>We report here a catalytic, Markovnikov selective, and scalable synthetic method for the synthesis of saturated sulfur heterocycles, which are found in the structures of pharmaceuticals and natural products, in one step from an alkenyl thioester. Unlike a potentially labile alkenyl thiol, an alkenyl thioester is stable and easy to prepare. The powerful Co catalysis via a cobalt hydride hydrogen atom transfer and radical-polar crossover mechanism enabled simultaneous cyclization and deprotection. The substrate scope was expanded by the extensive optimization of the reaction conditions and tuning of the thioester unit.</div>

Synthesis of Spongidine A, D and Petrosaspongiolide L Methyl Ester Using Pyridine C-H Functionalization

2019 ◽  
Author(s):  
Florian Bartels ◽  
Manuela Weber ◽  
Mathias Christmann
Keyword(s):  
Natural Products ◽  
Methyl Ester ◽  
Hydrogen Atom ◽  
Phospholipase A2 ◽  
Late Stage ◽  
Hydrogen Atom Transfer ◽  
Ring System ◽  
Tetracyclic Core ◽  
Intramolecular Hydrogen ◽  
Phospholipase A2 Inhibitors

<div>An efficient strategy for the synthesis of the potent phospholipase A2 inhibitors spongidine A and D is presented. The tetracyclic core of the natural products was assembled via an intramolecular hydrogen atom transfer‐initiated Minisci reaction. A divergent late‐stage functionalization of the tetracyclic ring system was also used to achieve a concise synthesis of petrosaspongiolide L methyl ester.</div>

Catalytic Synthesis of Cyclic Guanidines via Hydrogen Atom Transfer and Radical-Polar Crossover

2020 ◽  
Author(s):  
Shunya Ohuchi ◽  
Hiroki Koyama ◽  
Hiroki Shigehisa
Keyword(s):  
Hydrogen Atom ◽  
Functional Group ◽  
Hydrogen Atom Transfer ◽  
Catalytic Synthesis ◽  
Membered Ring ◽  
Biologically Active ◽  
Atom Transfer ◽  
Powerful Method ◽  
Protective Groups ◽  
The Common

A catalytic synthesis of cyclic guanidines, which are found in many biologically active compounds and natu-ral products, was developed, wherein transition-metal hydrogen atom transfer and radical-polar crossover were employed. This mild and functional-group tolerant process enabled the cyclization of alkenyl guanidines bearing common protective groups, such as Cbz and Boc. This powerful method not only provided the common 5- and 6-membered rings but also an unusual 7-membered ring. The derivatization of the products afforded various heterocycles. We also investigated the se-lective cyclization of mono-protected or hetero-protected (TFA and Boc) alkenyl guanidines and their further derivatiza-tions.

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