scholarly journals Photoelectron Spectroscopy of Mass-Selected Copper-Water Cluster Negative Ions

1995 ◽  
Vol 15 (2-4) ◽  
pp. 195-207 ◽  
Author(s):  
Fuminori Misaizu ◽  
Keizo Tsukamato ◽  
Masaomi Sanekata ◽  
Kiyokazu Fuke
Keyword(s):  
Photoelectron Spectroscopy ◽  
Negative Ions ◽  
Photoelectron Spectra ◽  
Negative Ion ◽  
Cluster Ions ◽  
Electron Detachment ◽  
Energy Bands ◽  
Size Dependent ◽  
Spectral Shifts ◽  
Metal Atoms

Negative-ion photoelectron spectroscopy has been applied in order to obtain size dependent information about the electronic structure of clusters of metal atoms solvated with polar molecules. In the present paper we have investigated the photoelectron spectra of Cu2-(H2O)n, cluster ions with 2 = 0–4 and also those of Cu2-(H2O)n, with n = 0 and 1. In the spectra of Cu2-(H2O)n, the lowest energy bands were assigned to the electron detachment from the CuOH-(H2O)n−1, which were produced in the source together with the above cluster ions. The observed bands for Cu2-(H2O)n were all assigned to the transitions to the states originating in the ground 2S and first excited 2D states of the Cu atom. The stepwise hydration for Cu- and Cu2- was discussed from the observed spectral shifts.

PHOTOELECTRON SPECTROSCOPY OF MASS-SELECTED METAL-WATER CLUSTER NEGATIVE IONS: Cu−(H2O)n AND Na−(H2O)n

1996 ◽  
Vol 03 (01) ◽  
pp. 405-410 ◽  
Author(s):  
F. MISAIZU ◽  
K. TSUKAMOTO ◽  
M. SANEKATA ◽  
K. FUKE
Keyword(s):  
Photoelectron Spectroscopy ◽  
Size Range ◽  
Water Clusters ◽  
Negative Ions ◽  
Photoelectron Spectra ◽  
Negative Ion ◽  
Atom Clusters ◽  
Metal Atoms ◽  
Vertical Detachment Energy ◽  
Pair State

The electronic structures of hydrated metal-atom clusters have been investigated by negative-ion photoelectron spectroscopy. We have obtained the photoelectron spectra of Cu −( H 2 O )n with n=0−4 and Na −( H 2 O )n with n=0−12. For the former clusters, we also detected the electron detachment from the CuOH −( H 2 O )n−1 which coexists with Cu −( H 2 O )n. The observed bands for both Cu −( H 2 O )n and Na −( H 2 O )n were all assigned to the transitions to the states originating in those of the metal atoms, which are shifted as a result of hydration. This result implies that the ground states of the neutral clusters still have a one-center character at the size range examined. In contrast, for the Na–water clusters, increasing character of the Rydberg-type ion-pair state in the negative-ion state is suggested from the vertical-detachment-energy dependence on the solvent number.

scholarly journals A novel rocket borne ion mass spectrometer with large mass range: instrument description and first flight results

2020 ◽  
Author(s):  
Joan Stude ◽  
Heinfried Aufmhoff ◽  
Hans Schlager ◽  
Markus Rapp ◽  
Frank Arnold ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Negative Ions ◽  
Mass Range ◽  
Large Mass ◽  
Molecular Ions ◽  
Negative Ion ◽  
Cluster Ions ◽  
The Arctic ◽  
Atmospheric Species ◽  
Smoke Particles

Abstract. We present a novel rocket borne ion mass spectrometer ROMARA (ROcket borne MAss spectrometer for Research in the Atmosphere) for measurements of atmospheric positive and negative ions (atomic, molecular and cluster ions) and positively and negatively charged meteor smoke particles. Our ROMARA instrument has, compared to previous rocket borne ion mass spectrometers, a markedly larger mass range of up to m/z 2000 and a larger sensitivity, particularly for meteor smoke particle detection. Mayor objectives of this first ROMARA flight included: a functional test of the ROMARA instrument, measurements between 55 km and 121 km in the mass range of atmospheric positive and negative ions, a first attempt to conduct mass spectrometric measurements in the mass range of meteor smoke particles with mass to charge ratios up to m/z 2000, and measurements inside a polar mesospheric winter echo layer as detected by ground based radar. Our ROMARA measurements took place on the Arctic island of Andøya/Norway around noon in April 2018 and represented an integral part of the PMWE rocket campaign. During the rocket flight, ROMARA was operated in a measurement mode, offering maximum sensitivity and the ability to qualitatively detect total ion signatures even beyond its mass resolving mass range. On this first ROMARA flight we were able to meet all of our objectives. We detected atmospheric species including positive atomic, molecular and cluster ions along with negative molecular ions up to about m/z 100. Above m/z 2000, ROMARA measured strong negative ion signatures, which are likely due to negatively charged meteor smoke particles.

Detachment cross sections for sulphur negative ion – rare gas collisions

1987 ◽  
Vol 65 (7) ◽  
pp. 735-738 ◽  
Author(s):  
B. Hird ◽  
M. Bruyère ◽  
S. Fafard
Keyword(s):  
Cross Sections ◽  
Negative Ions ◽  
Negative Ion ◽  
Rare Gas ◽  
Electron Detachment ◽  
Double Electron

The atomic cross sections for single and double electron detachment from sulphur negative ions in single collisions with He, Ne, Ar, Kr, and Xe are determined at collision energies between 12.5 and 110 keV.

Negative chlorine ion chemistry in the upper stratosphere and its application to an artificially created dense electron cloud

1995 ◽  
Vol 13 (3) ◽  
pp. 296-304 ◽  
Author(s):  
S. S. Prasad
Keyword(s):  
Major Ions ◽  
Negative Ions ◽  
Electron Cloud ◽  
Negative Ion ◽  
Cluster Ions ◽  
Aerosol Formation ◽  
Ion Chemistry ◽  
Catalytic Destruction ◽  
Three Body ◽  
Chlorine Ion

Abstract. This paper discusses new potential reactions of chlorine-bearing anions (negative ions) in the upper stratosphere. These reactions are then applied to the negative-ion chemistry following the injection of an electron cloud of very high density, of the order of 106-107 e- cm-3, in the 40-45-km region. The idea is to evaluate the recently proposed scheme to mitigate ozone depletion by converting the reactive chlorine atoms at these altitudes into Cl- ions which are unreactive towards ozone, i.e., electron scavenging of Cl. We find that the previously neglected photodetachment from Cl- is fast. For an overhead sun, this process may have a rate coefficient of 0.08 s-1 when multiple scattering is included. The rate could be even higher, depending on the ground albedo. Switching reaction between Cl-·H2O and HCl might lead to the formation of Cl-·HCl anion. Possible reactions of Cl-·H2O and Cl-·HCl with O atoms could produce ClO- and Cl-2. The production of ClO- in this manner is significant because Cl- having a high photodetachment rate constant would be regenerated in the very likely reactions of ClO- with O. When these possibilities are considered, then it is found that the chlorine anions may not be the major ions inside the electron cloud due to the rapid photodetachment from Cl-. Furthermore, in such a cloud, there may be the hazard that the Cl--Cl-·H2O-ClO--Cl- cycle amounts to catalytic destruction of two O atoms. Thus, the scheme could be risky if practised in the altitude region where atomic oxygen is an important constituent. Similar conclusions apply even if the ClO- species forms ClO-3 by three-body association with O2, instead of reacting with O. It must be emphasized that the present study is speculative at this time, because none of the relevant reactions have been investigated in the laboratory as yet. Nevertheless, it is very safe to say that the scheme of ozone preservation by electron scavenging of the upper stratospheric Cl is much less certain than implied in the studies reported by its original proponents, because those studies neglected the photodetachment from Cl- and made the highly unlikely assumption that the Cl-·H2O anion neither photodissociates nor reacts any further. The situation at the lower altitudes could be even more complex due to the formation of large cluster ions and the ion-induced aerosol formation. The lower atmospheric situation, therefore, requires much more study. The uncertainties in the scavenging scheme due to the electrostatic repulsion in the cloud should also be addressed. Despite the uncertainties about its environmental engineering usefulness, the emerging technology for artificial creation of plasmas, with any desired density and charge in the stratosphere, could have significant pure scientific values in the studies of stratospheric ion chemistry and ion-induced aerosol formation. Such studies have perennially suffered from the extremely low densities of the naturally occurring plasma.

scholarly journals A novel rocket-borne ion mass spectrometer with large mass range: instrument description and first-flight results

2021 ◽  
Vol 14 (2) ◽  
pp. 983-993
Author(s):  
Joan Stude ◽  
Heinfried Aufmhoff ◽  
Hans Schlager ◽  
Markus Rapp ◽  
Frank Arnold ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Negative Ions ◽  
Mass Range ◽  
Large Mass ◽  
Molecular Ions ◽  
Negative Ion ◽  
Cluster Ions ◽  
The Arctic ◽  
Atmospheric Species ◽  
Smoke Particles

Abstract. We present a novel rocket-borne ion mass spectrometer named ROMARA (ROcket-borne MAss spectrometer for Research in the Atmosphere) for measuring atmospheric positive and negative ions (atomic, molecular and cluster ions) and positively and negatively charged meteor smoke particles. Our ROMARA instrument has, compared to previous rocket-borne ion mass spectrometers, a markedly larger mass range of up to m/z 2000 and a larger sensitivity, particularly for meteor smoke particle detection. The major objectives of this first ROMARA flight included the following: a functional test of the ROMARA instrument, measurements between 55 and 121 km in the mass range of atmospheric positive and negative ions, a first attempt to conduct mass spectrometric measurements in the mass range of meteor smoke particles with mass-to-charge ratios up to m/z 2000, and measurements inside a polar mesospheric winter echo layer as detected by ground-based radar. Our ROMARA measurements took place on the Arctic island of Andøya, Norway, at around noon in April 2018 and represented an integral part of the polar mesospheric winter radar echo (PMWE) rocket campaign. During the rocket flight, ROMARA was operated in a measurement mode, offering maximum sensitivity and the ability to qualitatively detect total ion signatures even beyond its mass-resolving mass range. On this first ROMARA flight we were able to meet all of our objectives. We detected atmospheric species including positive atomic, molecular and cluster ions along with negative molecular ions up to about m/z 100. Above m/z 2000, ROMARA measured strong negative-ion signatures, which are likely due to negatively charged meteor smoke particles.

Intersubband Absorption in Gallium Arsenide Implanted with Silicon Negative Ions

2019 ◽  
Vol 19 (03) ◽  
pp. 1950019
Author(s):  
A. R. Yadav ◽  
S. K. Dubey ◽  
R. L. Dubey ◽  
N. Subramanyam ◽  
I. Sulania
Keyword(s):  
Gallium Arsenide ◽  
Binding Energy ◽  
Crystallite Size ◽  
Photoelectron Spectroscopy ◽  
Nir Spectroscopy ◽  
Negative Ions ◽  
Core Level ◽  
Photoelectron Spectra ◽  
Gaas Sample ◽  
X Ray

Gallium arsenide (GaAs) implanted with silicon forming intersubband of SiGaAs is a promising material for making novel electronic and optoelectronic devices. This paper is focused on finding optimum fluence condition for formation of intersubband of SiGaAs in GaAs sample after implantation with 50[Formula: see text]keV silicon negative ions with fluences varying between [Formula: see text] and [Formula: see text] ions cm[Formula: see text]. The GaAs samples were investigated using X-ray photoelectron spectroscopy (XPS), UV-Vis.-NIR spectroscopy and X-ray diffraction (XRD) techniques. The X-ray photoelectron spectra for unimplanted sample showed peaks at binding energy of 18.74[Formula: see text]eV and 40.74[Formula: see text]eV indicating Ga3d and As3d core level, whereas the corresponding core level peaks for implanted sample were observed at binding energy of 19.25[Formula: see text]eV and 41.32[Formula: see text]eV. The shift in Ga3d and As3d core levels towards higher binding energy side in the implanted sample with respect to unimplanted sample were indicative of change in chemical state environment of Ga–As bond. The relative atomic percentage concentration of elemental composition measured using casa XPS software showed change in As/Ga ratio from 0.89 for unimplanted sample to 1.13 for sample implanted with the fluence of [Formula: see text] ion cm[Formula: see text]. The UV-Vis-NIR spectra showed absorption band between 1.365[Formula: see text]eV and 1.375[Formula: see text]eV due to the formation of intersubband of SiGaAs for fluences greater than [Formula: see text] ion cm[Formula: see text]. The GaAs crystallite size calculated using Brus formula was found to vary between 162[Formula: see text]nm and 540[Formula: see text]nm, respectively. The XRD spectra showed the presence of Bragg’s peak at 53.98∘ indicating (311) silicon reflection. The silicon crystallite size determined from full width at half maxima (FWHM) of (311) XRD peak was found to vary between 110[Formula: see text]nm and 161[Formula: see text]nm, respectively.

scholarly journals Determination of the atmospheric lifetime and global warming potential of sulfur hexafluoride using a three-dimensional model

2017 ◽  
Vol 17 (2) ◽  
pp. 883-898 ◽  
Author(s):  
Tamás Kovács ◽  
Wuhu Feng ◽  
Anna Totterdill ◽  
John M. C. Plane ◽  
Sandip Dhomse ◽  
...  
Keyword(s):  
Global Warming ◽  
Electron Density ◽  
Sulfur Hexafluoride ◽  
Climate Model ◽  
Negative Ions ◽  
Cluster Ions ◽  
Ion Chemistry ◽  
Three Dimensional Model ◽  
Atmospheric Lifetime ◽  
Metal Atoms

Abstract. We have used the Whole Atmosphere Community Climate Model (WACCM), with an updated treatment of loss processes, to determine the atmospheric lifetime of sulfur hexafluoride (SF6). The model includes the following SF6 removal processes: photolysis, electron attachment and reaction with mesospheric metal atoms. The Sodankylä Ion Chemistry (SIC) model is incorporated into the standard version of WACCM to produce a new version with a detailed D region ion chemistry with cluster ions and negative ions. This is used to determine a latitude- and altitude-dependent scaling factor for the electron density in the standard WACCM in order to carry out multi-year SF6 simulations. The model gives a mean SF6 lifetime over an 11-year solar cycle (τ) of 1278 years (with a range from 1120 to 1475 years), which is much shorter than the currently widely used value of 3200 years, due to the larger contribution (97.4 %) of the modelled electron density to the total atmospheric loss. The loss of SF6 by reaction with mesospheric metal atoms (Na and K) is far too slow to affect the lifetime. We investigate how this shorter atmospheric lifetime impacts the use of SF6 to derive stratospheric age of air. The age of air derived from this shorter lifetime SF6 tracer is longer by 9 % in polar latitudes at 20 km compared to a passive SF6 tracer. We also present laboratory measurements of the infrared spectrum of SF6 and find good agreement with previous studies. We calculate the resulting radiative forcings and efficiencies to be, on average, very similar to those reported previously. Our values for the 20-, 100- and 500-year global warming potentials are 18 000, 23 800 and 31 300, respectively.

scholarly journals Determination of the atmospheric lifetime and global warming potential of sulphur hexafluoride using a three-dimensional model

2016 ◽  
Author(s):  
Tamás Kovács ◽  
Wuhu Feng ◽  
Anna Totterdill ◽  
John M. C. Plane ◽  
Sandip Dhomse ◽  
...  
Keyword(s):  
Global Warming ◽  
Electron Density ◽  
Climate Model ◽  
Three Dimensional ◽  
Negative Ions ◽  
Cluster Ions ◽  
Ion Chemistry ◽  
Three Dimensional Model ◽  
Atmospheric Lifetime ◽  
Metal Atoms

Abstract. We have used the Whole Atmosphere Community Climate Model (WACCM), with an updated treatment of loss processes, to determine the atmospheric lifetime of SF6. The model includes the following SF6 removal processes: photolysis, electron attachment and reaction with mesospheric metal atoms. The Sodankylä Ion Chemistry (SIC) model is incorporated into the standard version of WACCM to produce a new version with a detailed D region ion chemistry with cluster ions and negative ions. This is used to determine a latitude- and altitude-dependent scaling factor for the electron density in the standard WACCM in order to carry out multi-year SF6 simulations. The model gives a mean SF6 lifetime over a 11-year solar cycle (τ) of 1278 years (with a range from 1120 to 1475 years), which is much shorter than the currently widely used value of 3200 years, due to the larger contribution (97.4 %) of the modelled electron density to the total atmospheric loss. The loss of SF6 by reaction with mesospheric metal atoms (Na and K) is far too slow to affect the lifetime. We investigate how this shorter atmospheric lifetime impacts the use of SF6 to derive stratospheric age-of-air. The age-of-air derived from this shorter lifetime SF6 tracer is longer by 9 % in polar latitudes at 20 km compared to a passive SF6 tracer. We also present laboratory measurements of the infrared spectrum of SF6 and find good agreement with previous studies. We calculate the resulting radiative forcings and efficiencies to be, on average, very similar to those reported previously. Our values for the 20, 100 and 500-year global warming potentials are 18,000, 23,800 and 31,300, respectively.

Theory of electron detachment in collisions of negative ions with atoms II. Survival probability, differential elastic cross section, and total detachment cross section for the H - –He system

1982 ◽  
Vol 379 (1776) ◽  
pp. 209-216 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Preceding Paper ◽  
Negative Ions ◽  
Elastic Cross Section ◽  
Negative Ion ◽  
Total Probability ◽  
Electron Detachment ◽  
Close Coupling ◽  
Probability Of Survival

The close-coupling theory of electron detachment, developed in the preceding paper I, is used to calculate the probability of survival of the negative ion, and the total probability of electron detachment. Neglect of a term reduces the formulas to more familiar ones, which are then used to calculate differential elastic cross sections and total detachment cross sections for the H - –He and D - –He systems. Good agreement with experi­mental results is obtained.

scholarly journals Modification of Wood with Monoethanolamino-borate by The Data of X-Ray Photoelectron Spectroscopy

2018 ◽  
Vol 196 ◽  
pp. 04005
Author(s):  
Irina Stepina ◽  
Irina Kotlyarova
Keyword(s):  
Particle Size ◽  
Photoelectron Spectroscopy ◽  
Model Compound ◽  
Hydrolytic Stability ◽  
Photoelectron Spectra ◽  
Wood Cellulose ◽  
Rapid Loss ◽  
X Ray ◽  
Wood Protection ◽  
Cellulose Materials

The difficulty of wood protection from biocorrosion and fire is due to the fact that modifiers in use are washed out from the surface of the substrate under the influence of environmental factors. This results in a rapid loss of the protective effect and other practically important wood characteristics caused by the modification. To solve this problem is the aim of our work. Here, monoethanolaminoborate is used as a modifier, where electron-donating nitrogen atom provides a coordination number equal to four to a boron atom, which determines the hydrolytic stability of the compounds formed. Alpha-cellulose ground mechanically to a particle size of 1 mm at most was used as a model compound for the modification. X-ray photoelectron spectra were recorded on the XSAM-800 spectrometer (Kratos, UK). Prolonged extraction of the modified samples preceded the registration of the photoelectron spectra to exclude the fixation of the modifier molecules unreacted with cellulose. As a result of the experiment, boron and nitrogen atoms were found in the modified substrate, which indicated the hydrolytic stability of the bonds formed between the modifier molecules and the substrate. Therefore monoethanolaminoborate can be considered as a non-extractable modifier for wood-cellulose materials.

Sign in / Sign up

Export Citation Format

Share Document