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Abstract We report new measurements of branching fractions for 20 UV and blue lines in the spectrum of neutral silicon (Sii) originating in the 3s23p4s3Po1,2,1Po1, and 3s3p31Do1,2upper levels. Transitions studied include both strong, nearly pure LS multiplets as well as very weak spin-forbidden transitions connected to these upper levels. We also report a new branching fraction measurement of the4P1/2–2Po1/2,3/2intercombination lines in the spectrum of singly ionized silicon (Siii). The weak spin-forbidden lines of Siiand Siiiprovide a stringent test on recent theoretical calculations, to which we make comparison. The branching fractions from this study are combined with previously reported radiative lifetimes to yield transition probabilities and log(gf) values for these lines. We apply these new measurements to abundance determinations in five metal-poor stars.
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Visible‐Light‐Mediated Controlled Radical Branching Polymerization in Water
Abstract Hyperbranched polymethacrylates were synthesized by green‐light‐induced atom transfer radical polymerization (ATRP) under biologically relevant conditions in the open air. Sodium 2‐bromoacrylate (SBA) was prepared in situ from commercially available 2‐bromoacrylic acid and used as a water‐soluble inibramer to induce branching during the copolymerization of methacrylate monomers. As a result, well‐defined branched polymethacrylates were obtained in less than 30 min with predetermined molecular weights (36 000<Mn<170 000), tunable degree of branching, and low dispersity values (1.14≤Đ≤1.33). Moreover, the use of SBA inibramer enabled the synthesis of bioconjugates with a well‐controlled branched architecture.
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- Award ID(s):
- 2202747
- PAR ID:
- 10397935
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 62
- Issue:
- 10
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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