Fine Structure of the Hydrogen Atom by a Microwave Method,

Lamb, Willis E.; Retherford, Robert C.

doi:10.1016/b978-0-08-029160-4.50018-x

Cited by 4 publications

(5 citation statements)

References 4 publications

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“…Polar solvents such as ethanol and methanol undergo lesser microwave absorption then water due to their lower ϵ values but their overall heating remains efficient . Hexane and other less polar solvents are transparent to microwaves and hence do not produce any heat . This property of solvents frequently used in perfumery is particularly interesting as it avoids thermodegradation of specific compounds of interest.…”

Section: Innovative Techniques For Green Extractionmentioning

confidence: 99%

Extraction of Natural Fragrance Ingredients: History Overview and Future Trends

Burger¹,

Plainfossé

Brochet³

et al. 2019

Chemistry & Biodiversity

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For centuries, perfumes consisted in a combination of natural ingredients, mainly of plant origin. From the 19th century on, the advent of organic synthesis enabled the deployment of multiple synthetic olfactory notes, enriching significantly the perfumers’ portfolio. Chemistry is ever since the foundation of modern perfumery. However, sustainable‐minded consumers, massively rejecting synthetics for safety and ecological issues, engaged a global return to nature in numerous sectors, and the fragrance industry is not outdone. Sustainable extraction of natural products, making use of innovative technologies, process intensification and agro‐based solvents, constitutes the answer to develop eco‐conceived fragrant ingredients covering every olfactory family without endangering biodiversity any further. The objective of this review is to draw a clear picture of where those technological advances are today and to assess the ones that may be effectively transposed at the industrial scale tomorrow.

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Section: Innovative Techniques For Green Extractionmentioning

confidence: 99%

Extraction of Natural Fragrance Ingredients: History Overview and Future Trends

Burger¹,

Plainfossé

Brochet³

et al. 2019

Chemistry & Biodiversity

View full text Add to dashboard Cite

show abstract

“…There are other relativistic effects such as the Lamb shift in the spectrum of the H atom, which can no longer be explained using the theory of special relativity as it presents an interaction of the H electron with the vacuum. Instead, the Lamb shift requires a theoretical description employing the theory of quantum electrodynamics (QED) developed by Schwinger et al.…”

Section: Importance Of Relativistic Effects In Chemistrymentioning

confidence: 99%

Dirac‐exact relativistic methods: the normalized elimination of the small component method

Cremer

Zou

Filatov

2014

WIREs Comput Mol Sci

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Dirac‐exact relativistic methods, i.e., 2‐ or 1‐component methods which exactly reproduce the one‐electron energies of the original 4‐component Dirac method, have established a standard for reliable relativistic quantum chemical calculations targeting medium‐ and large‐sized molecules. Their development was initiated and facilitated in the late 1990s by Dyall's development of the normalized elimination of the small component (NESC). Dyall's work has fostered the conversion of NESC and related (later developed) methods into routinely used, multipurpose Dirac‐exact methods by which energies, first‐order, and second‐order properties can be calculated at computational costs, which are only slightly higher than those of nonrelativistic methods. This review summarizes the development of a generally applicable 1‐component NESC algorithm leading to the calculation of reliable energies, geometries, electron density distributions, electric moments, electric field gradients, hyperfine structure constants, contact densities and Mössbauer isomer shifts, nuclear quadrupole coupling constants, vibrational frequencies, infrared intensities, and static electric dipole polarizabilities. In addition, the derivation and computational possibilities of 2‐component NESC methods are discussed and their use for the calculation of spin‐orbit coupling (SOC) effects in connection with spin‐orbit splittings and SOC‐corrected energies are demonstrated. The impact of scalar relativistic and spin‐orbit effects on molecular properties is presented. WIREs Comput Mol Sci 2014, 4:436–467. This article is categorized under: Electronic Structure Theory > Ab Initio Electronic Structure Methods

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“…The great wartime advances in microwave techniques in the vicinity of three centimeters wavelength make possible the use of new physical tools for a study of the n =2 fine-structure states of the hydrogen atom (Lamb and Retherford, 1947). While Rabi and Zacharias were applying themselves to measuring the separation of the hyperfine energy levels in the ground state of the hydrogen atom, in order to com-60 The first to undertake such an atomic-beam frequency standard was Harold Lyons at the U.S. National Bureau of Standards in 1948-with detailed guidance by Rabi's lieutenant in the Columbia molecular-beams lab, Polykarp Kusch.…”

Section: F Molecular-beam Magnetic Resonance Spectroscopymentioning

confidence: 99%

“…In the prewar decade these predictions were examined and reexamined by optical spectroscopists, working here, once again, at the limits of precision of their techniques. "The various spectroscopic works," Lamb and Retherford (1947) noted in their initial publication, have alternated between finding confirmation of the theory and discrepancies of as much as eight percent.…”

Section: F Molecular-beam Magnetic Resonance Spectroscopymentioning

confidence: 99%

"Swords into ploughshares": Breaking new ground with radar hardware and technique in physical research after World War II

Forman

1995

Rev. Mod. Phys.

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A survey is offered of applications to fundamental physical research, in the years immediately following World War II, of the instrumentalities developed for radar during that war. Attention is given to radar astronomy and radio astronomy, linear and cyclical accelerators, microwave spectroscopy, molecular beams, nuclear magnetic resonance, electron paramagnetic and ferromagnetic resonance, measurements of resistivity at high frequencies in metals and of second sound in helium II, and to the concepts of information and signal-to-noise ratio as basic to the design and analysis of experiments. In conjunction with this survey, consideration is given to the autonomy of physics as a knowledge-producing enterprise, framed as a question of continuity in research directions. As that question implies a baseline, the survey of postwar applications is preceded by a survey of those prewar directions of physical research requiring the highest available radio frequencies. Some 500 references are given.

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Fine Structure of the Hydrogen Atom by a Microwave Method,

Cited by 4 publications

References 4 publications

Extraction of Natural Fragrance Ingredients: History Overview and Future Trends

Extraction of Natural Fragrance Ingredients: History Overview and Future Trends

Dirac‐exact relativistic methods: the normalized elimination of the small component method

"Swords into ploughshares": Breaking new ground with radar hardware and technique in physical research after World War II

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