Semiclassical study on photodetachment of hydrogen negative ion in a harmonic potential confined by a quantum well

2021 ◽  
Vol 76 (5) ◽  
pp. 407-416
Author(s):  
De-hua Wang
Keyword(s):  
Quantum Well ◽  
Ion Trap ◽  
Negative Ion ◽  
Harmonic Potential ◽  
Outgoing Wave ◽  
Harmonic Frequency ◽  
Tooth Structure ◽  
Large Size ◽  
Closed Orbits ◽  
Low Dimensional

Abstract We have studied the photodetachment dynamics of the H− ion in a harmonic potential confined in a quantum well for the first time. The closed orbits of the detached electron in a confined harmonic potential are found and the photodetachment spectra of this system are calculated. It is interesting to find that the photodetachment spectra depend sensitively on the size of the quantum well and the harmonic frequency. For smaller size of the quantum well, the harmonic potential can be considered as a perturbation, the interference effect between the returning electron wave bounced back by the quantum well and the initial outgoing wave is very strong, which makes the photodetachment spectra exhibits an irregular saw-tooth structure. With the increase of the size of the quantum well, the photodetachment spectra oscillates complicatedly in the higher energy region. For very large size of the quantum well, the photodetachment spectra approach to the case in a free harmonic potential, which is a regular saw-tooth structure. In addition, the harmonic frequency can also affect the photodetachment spectra of this system greatly. Our work provides a new method for the study of spatially confined low-dimensional systems and may guide the future experimental research for the photodetachment dynamics in the ion trap.

Photodetachment of the H– ion in a forced harmonic potential

2020 ◽  
Vol 98 (9) ◽  
pp. 883-892
Author(s):  
De-hua Wang
Keyword(s):  
Electric Field ◽  
Cross Section ◽  
Closed Orbit ◽  
Negative Ions ◽  
Resonance Phenomenon ◽  
Harmonic Potential ◽  
Outgoing Wave ◽  
Harmonic Frequency ◽  
Classical Motion ◽  
Photodetachment Cross Section

The photodetachment of a H– ion in a forced harmonic potential driven by a general time-dependent oscillating electric field has been investigated in the semi-classical closed orbit theory for the first time. It is found that the driven electric field frequency can affect the photodetachment cross-section of this system greatly. If the frequency of the driving electric field is equal to the harmonic frequency, a resonance phenomenon occurs in the classical motion of the detached electron. The interference effect between the returning electron wave travelling along the closed orbit with the initial outgoing wave gets stronger, causing the photodetachment cross-section to oscillate in a complicated manner. When the frequency of the driving electric field is unequal to the harmonic frequency, the driving electric field can weaken or strengthen the oscillatory structure in the photodetachment cross-section. In addition, the strength and initial phase in the driving electric field can also influence the photodetachment dynamics of the system. Our work provides a new method for controlling the photodetachment of negative ions in a harmonic potential and may guide future experimental research for cavity dynamics or in the ion trap.

Synthetic Control over Quantum Well Width Distribution and Carrier Migration in Low-Dimensional Perovskite Photovoltaics

2018 ◽  
Vol 140 (8) ◽  
pp. 2890-2896 ◽  
Author(s):  
Andrew H. Proppe ◽  
Rafael Quintero-Bermudez ◽  
Hairen Tan ◽  
Oleksandr Voznyy ◽  
Shana O. Kelley ◽  
...  
Keyword(s):  
Quantum Well ◽  
Synthetic Control ◽  
Width Distribution ◽  
Quantum Well Width ◽  
Low Dimensional

scholarly journals Online atmospheric pressure chemical ionization ion trap mass spectrometry (APCI-IT-MS<sup>n</sup>) for measuring organic acids in concentrated bulk aerosol – a laboratory and field study

2013 ◽  
Vol 6 (2) ◽  
pp. 431-443 ◽  
Author(s):  
A. L. Vogel ◽  
M. Äijälä ◽  
M. Brüggemann ◽  
M. Ehn ◽  
H. Junninen ◽  
...  
Keyword(s):  
Organic Acids ◽  
Atmospheric Pressure ◽  
Ion Trap ◽  
Atmospheric Pressure Chemical Ionization ◽  
Oxidation Products ◽  
Negative Ion ◽  
Pressure Chemical Ionization ◽  
Pressure Chemical ◽  
Negative Ion Mode ◽  
Pinic Acid

Abstract. The field application of an aerosol concentrator in conjunction with an atmospheric pressure chemical ionization ion trap mass spectrometer (APCI-IT-MS) at the boreal forest station SMEAR II at Hyytiälä, Finland, is demonstrated in this study. APCI is a soft-ionization technique allowing online measurements of organic acids in the gas and particle phase. The detection limit for the acid species in the particle phase was improved by a factor of 7.5 to 11 (e.g. ∼40 ng m3 for pinonic acid) by using the miniature versatile aerosol concentration enrichment system (mVACES) upstream of the mass spectrometer. The APCI-IT-MS was calibrated in the negative ion mode with two biogenic organic acid standards – pinic acid and pinonic acid. Pinic acid was used as a surrogate for the quantification of the total amount of organic acids in the ambient aerosol based on the total signal intensities in the negative ion mode. The results were compared with the total organic signal of a C-ToF-AMS during the HUMPPA-COPEC 2010 field campaign. The campaign average contribution of organic acids measured by APCI-IT-MS to the total submicron organic aerosol mass was estimated to be about 60%, based on the response of pinic acid. Very good correlation between APCI-IT-MS and C-ToF-AMS (Pearson's R = 0.94) demonstrates soft-ionization mass spectrometry as a complimentary technique to AMS with electron impact ionization. MS2 studies of specific m/z ratios recorded during the HUMPPA-COPEC 2010 field campaign were compared to MS2 studies of selected monoterpene oxidation products formed in simulation chamber experiments. The comparison of the resulting fragments shows that oxidation products of the main VOCs emitted at Hyytiälä (α-pinene and Δ3-carene) cannot account for all of the measured fragments. Possible explanations for those unaccounted fragments are the presence of unidentified or underestimated biogenic SOA precursors, or that different products are formed by a different oxidant mixture of the ambient air compared to the chamber ozonolysis.

scholarly journals Discrimination of GalNAc (4S/6S) sulfation sites in chondroitin sulfate disaccharides by chip-based nanoelectrospray multistage mass spectrometry

2009 ◽  
Vol 7 (4) ◽  
pp. 752-759 ◽  
Author(s):  
Corina Flangea ◽  
Alina Serb ◽  
Catalin Schiopu ◽  
Sorin Tudor ◽  
Eugen Sisu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chondroitin Sulfate ◽  
Ion Trap ◽  
High Capacity ◽  
Ester Group ◽  
Negative Ion ◽  
Post Translational Modification ◽  
Spectrometric Data ◽  
Group Position ◽  
Fragmentation Patterns

AbstractSulfation pattern within chondroitin sulfate (CS) glycosaminoglycan (GAG) chains is an important post-translational modification that regulates their interaction with proteins. In this context, development of highly efficient and reproducible analytical methods for the investigation of CS sulfation patterns is of high necessity. In this study we report a novel method for straightforward determination of N-acetylgalactosamine (GalNAc) sulfation sites in chondroitin sulfate disaccharides. Our protocol involves combining fully automated chip-based nanoelectrospray (nanoESI) for analyte infusion and ionization in negative ion mode with multistage (MSn) collision-induced dissociation (CID) high capacity ion trap (HCT) mass spectrometry for generation of sequence ions diagnostic for identification of sulfate ester group position within GalNAc residues. The feasibility of this approach is here demonstrated on chondroitin 6-O-sulfate and chondroitin 4-O-sulfate disaccharides. Fragmentation patterns obtained by MS2 and MS3 sequencing stages provided first mass spectrometric data from which sulfation site(s) within GalNAc monosaccharide ring could be unequivocally deciphered. Hence, the method allowed discriminating 4S/6S sulfation sites solely on the basis of MS and multistage MS evidence.

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