Photoionization cross section measurements of the excited states of cobalt in the near-threshold region

Zheng, Xianfeng; Zhou, X. K.; Cheng, Zaiqi; Jia, Dandan; Qu, Zehua; G, Yao; Zhang, Xianyi; Cui, Zhifeng

doi:10.1063/1.4898326

Cited by 6 publications

(5 citation statements)

References 27 publications

(24 reference statements)

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“…Mechanism of evolution and proliferation of ARGs in pathogens or environmental microbes is still elusive. Antibiotic-resistant bacteria and resistant genes are found in every habitat including isolated ecosystem of hundreds or thousand years [32–34]. Pathogenic and non-pathogenic bacteria belonging to the mesophilic and psychrophilic environment has been widely studied for antibiotic resistance.…”

Section: Discussionmentioning

confidence: 99%

Diversity analysis and metagenomic insights into the Antibiotic Resistance and Metal Resistances among Hot Spring Bacteriobiome-insinuating inherent environmental baseline levels of Antibiotic and Metal tolerance

Das

et al. 2019

Preprint

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34Mechanisms of occurrence and expressions of antibiotic resistance genes (ARGs) in 35 thermophilic bacteria are still unknown owing to limited research and data. The evolution and 36 proliferation of ARGs in the thermophilic bacteria is unclear and needs a comprehensive study. 37 In this research, comparative profiling of antibiotic resistance genes and metal tolerance genes 38 among the thermophilic bacteria has been done by culture-independent functional metagenomic 39 methods. Metagenomic analysis showed the dominance of Proteobacteria, Actinobacteria. 40 Firmicutes and Bacteroidetes in these hot springs. ARG analysis through shotgun gene 41 sequencing was found to be negative in case of thermophilic bacteria. However, few of genes 42 were detected but they were showing maximum similarity with mesophilic bacteria. 43Concurrently, metal resistance genes were also detected in the metagenome sequence of hot 44 springs. Detection of metal resistance gene and absence of ARG's investigated by whole genome 45 sequencing, in the reference genome sequence of thermophilic Geobacillus also conveyed the 46 same message. This evolutionary selection of metal resistance over antibiotic genes may have 47 been necessary to survive in the geological craters which are full of different metals from earth 48 sediments rather than antibiotics. Furthermore, the selection could be environment driven 49 depending on the susceptibility of ARG's in thermophilic environment as it reduces the chances 50 of horizontal gene transfer. With these findings this article highlights many theories and 51 culminates different scopes to study these aspects in thermophiles. 52 53 54 55 56 58The generic term "antibiotic" is used to denote any class of chemotherapeutic agents that inhibits 59 or kills microbes (pathogens) by specific interactions with microbial targets [1]. However, the 60 increasing rate of antibiotic resistance in microorganisms is a critical challenge to public health 61 [2-4]. The spread of antibiotic-resistant superbug is posing a threat to morbidity and mortality 62 worldwide [5]. The potential clinical threat of antibiotic-resistant bacteria has abled to gain 63 attention with a focus on the identification and management of environmental reservoirs of 64 antibiotic resistance genes (ARGs). Though antibiotic resistance occurs naturally, human activity 65 including misuse or overuse of antibiotics has exacerbated the scenario. Pathogenic and non-66 pathogenic bacteria belonging to the mesophilic world has been extensively studied in terms of 67 antibiotic resistance. However, researchers have paid very less attention to antibiotic resistance 68 in thermophilic bacteria. The distribution of ARGs and their antibiotic resistance profile needs 69 attention to avert the possible emergence of an opportunistic pathogen of thermophilic origin. 70 Extensive application of thermophilic bacteria in biotechnological and industrial fields also 71 supports the possibility of future pathogenic emergence with high antibiotic resistan...

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Section: Discussionmentioning

confidence: 99%

Diversity analysis and metagenomic insights into the Antibiotic Resistance and Metal Resistances among Hot Spring Bacteriobiome-insinuating inherent environmental baseline levels of Antibiotic and Metal tolerance

Das

et al. 2019

Preprint

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“…The ionization efficiency of Co in the hot-cavity laser ion source was measured using a sample containing 2.044×10 17 neutral Co atoms and the ionization scheme B that employs the f 4 F, J=11/2 state in the second step and a Rydberg transition (n=9 member of the autoionizing Rydberg series III) in the last step. An overall ionization efficiency of about 18% was obtained, under non optimized conditions for ion extraction.…”

Section: Discussionmentioning

confidence: 99%

“…To measure the overall ionization efficiency, a calibrated sample containing 2.044×10 17 Co atoms was made from 20 μl of 1000 ppm cobalt atomic absorption standard solution, dried on a 0.001 inch thick Ti foil and then wrapped in the foil. This sample was placed in the ion source.…”

Section: Ionization Efficiencymentioning

confidence: 99%

“…At the facilities based on the Isotope Separator On-Line (ISOL) production method, highly selective resonant laser ionization has been required to produce pure beams of neutron-rich Co isotopes needed for most nuclear experiments, effectively suppressing the unwanted isobaric background. Studies of resonant ionization of Co atoms have been limited [13][14][15][16][17][18][19] and mainly employed dye lasers. Recently, suitable Ti:Sapphire lasers have been developed and are increasingly used for the production of exotic radioactive ion beams because of their advantage of reliable and maintenance-free all-solidstate laser technology.…”

Section: Introductionmentioning

confidence: 99%

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Resonant ionization spectroscopy of autoionizing Rydberg states in cobalt and redetermination of its ionization potential

Liu¹,

Gottwald²,

Mattolat³

et al. 2017

J. Phys. B: At. Mol. Opt. Phys.

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Multi-step resonance ionization spectroscopy of cobalt has been performed using a hot-cavity laser ion source and three Ti:Sapphire lasers. The photoionization spectra revealed members of five new autoionizing Rydberg series that originate from three different lower levels of 3d 7 4s5s h 4 F 9/2 , 3d 7 4s4d f 4 G 11/2 , and 3d 7 4s4d f 4 H 13/2 and converge to the first four excited states of singly ionized Co. The analyses of the Rydberg series yield 63 564.689±0.036 cm −1 as the first ionization potential of Co, which is an order of magnitude more accurate than the previous estimation. Using a three-step resonance ionization scheme that employs an autoinizing Rydberg state in the last transition, we obtained an overall ionization efficiency of about 18% for Co.

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“…Another method to explore the situation experimentally is to use one laser pulse to excite F@C 60 by inducing an electron transfer and another pulse to ionize the hybrid levels to probe excited state cross sections. Such two-color two-step photoionization measurement techniques have been used earlier [48][49][50]. Based on this technique, an electron can be selectively promoted from a chosen C 60 level, namely C 60 HOMO or a hybrid level, to form metastable configurations.…”

Section: Experimental Possibilitiesmentioning

confidence: 99%

Electron vacancy-level dependent hybrid photoionization of the F⁻@ C60+ molecule: a novel effect

Ali¹,

Taylor²,

Dennis³

et al. 2022

J. Phys. B: At. Mol. Opt. Phys.

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Our previous studies [J. Phys. B 53, 125101 (2020); Euro. Phys. J. D 74, 191 (2020)] have predicted that the atom-fullerene hybrid photoionization properties for X = Cl, Br and I endohedrally conﬁned in C60 are diﬀerent before and after an electron transfers from C60 to the halogen. It was further found as a rule that the ionization dynamics is insensitive to the C60level the electron originates from to produce X−@C60+ . In the current study, we report an exception to this rule in F@C60. It is found that when the electron vacancy is situated in the C60level that participates in the hybridization in F−@C60+, the mixing becomes dramatically large leading to strong modiﬁcations in the photoionization of the hybrid levels. This novel eﬀect is fundamentally based on a level-crossing phenomenon driven by the electron transfer in F@C60. But when the vacancy is at any other pure level of C60, the level-invariance is retained showing weak hybridization. Even though this case of F@C60 is an exception in the halogen@C60 series, the phenomenon can be more general and can occur with compounds of other atoms caged in a variety of fullerenes. Possible experimental studies are suggested to benchmark the present results.

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Photoionization cross section measurements of the excited states of cobalt in the near-threshold region

Cited by 6 publications

References 27 publications

Diversity analysis and metagenomic insights into the Antibiotic Resistance and Metal Resistances among Hot Spring Bacteriobiome-insinuating inherent environmental baseline levels of Antibiotic and Metal tolerance

Diversity analysis and metagenomic insights into the Antibiotic Resistance and Metal Resistances among Hot Spring Bacteriobiome-insinuating inherent environmental baseline levels of Antibiotic and Metal tolerance

Resonant ionization spectroscopy of autoionizing Rydberg states in cobalt and redetermination of its ionization potential

Electron vacancy-level dependent hybrid photoionization of the F⁻@ C60+ molecule: a novel effect

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Photoionization cross section measurements of the excited states of cobalt in the near-threshold region

Cited by 6 publications

References 27 publications

Diversity analysis and metagenomic insights into the Antibiotic Resistance and Metal Resistances among Hot Spring Bacteriobiome-insinuating inherent environmental baseline levels of Antibiotic and Metal tolerance

Diversity analysis and metagenomic insights into the Antibiotic Resistance and Metal Resistances among Hot Spring Bacteriobiome-insinuating inherent environmental baseline levels of Antibiotic and Metal tolerance

Resonant ionization spectroscopy of autoionizing Rydberg states in cobalt and redetermination of its ionization potential

Electron vacancy-level dependent hybrid photoionization of the F−@ C60+ molecule: a novel effect

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Electron vacancy-level dependent hybrid photoionization of the F⁻@ C60+ molecule: a novel effect