Fluorescence from the A 2Σ+ state suggests a non-Franck–Condon N2O+• vibrational state population after keV collisional activation with helium

2011 ◽  
Vol 89 (3) ◽  
pp. 303-309 ◽  
Author(s):  
Yawei Lin ◽  
Paul M. Mayer
Keyword(s):  
Vibrational State ◽  
Reference Data ◽  
Laboratory Frame ◽  
Translational Energy ◽  
Parent Molecule ◽  
Charge Coupled Device ◽  
Band Emission ◽  
Ccd Detector ◽  
Franck Condon ◽  
Curve Crossing

A commercial analytical mass spectrometer coupled with a spectrograph and charge-coupled device (CCD) detector was used to obtain the collision-induced emission (CIE) spectra (190–1020 nm) from ion–molecule collisions between N2O+• and He at laboratory frame collision energies of 4–8 keV. The observed emissions were from the A 2Σ+ → X 2Π+ system of N2O+•, excited fragments of the parent molecule, and the target gas. The relative emission intensities of the N2O+• ions and their fragments were independent of the ion translational energy within the 4–8 keV range, confirming the curve-crossing mechanism for translational-to-internal energy transfer in this system. Band emission intensities of [Formula: see text] and [Formula: see text] relative to the [Formula: see text] band within the N2O+• (A → X) system have been measured and compared with reference data. The results indicated that the collisionally excited ion has a decidedly non-Franck–Condon vibrational state distribution.

scholarly journals X-ray transmission grating spectrometer with CCD detector for laser plasma studies

1991 ◽  
Vol 9 (2) ◽  
pp. 579-591 ◽  
Author(s):  
L. Pína ◽  
H. Fiedorowicz ◽  
M. O. Koshevoi ◽  
A. A. Rupasov ◽  
B. Rus ◽  
...  
Keyword(s):  
Laser Plasma ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Array Detector ◽  
Charge Coupled Device ◽  
X Ray ◽  
Transmission Grating ◽  
Hot Plasma ◽  
Ccd Detector ◽  
Wet Processing

A program is under way to develop methods and instrumentation based on charge-coupled device (CCD) sensors for hot plasma diagnostics. We have developed a new X-ray spectrometer in which a freestanding X-ray transmission grating is coupled to a CCD linear array detector with electronic digitized readout replacing film and its wet processing. This instrument measures time-integrated pulsed X-ray spectra with moderate spectral resolution (δλ ≤ 0.6 nm) over a broad spectral range (0.3–2 keV) with high sensitivity, linearity, and large dynamic range. The performance of the device was tested using laser plasma as the X-ray source.

Synchrotron Microtomography of Composites

1988 ◽  
Vol 143 ◽  
Author(s):  
S. R. Stock ◽  
J. H. Kinney ◽  
T. M. Breunig ◽  
U. Bonse ◽  
S. D. Antolovich ◽  
...  
Keyword(s):  
Charge Coupled Device ◽  
High Brightness ◽  
X Ray ◽  
Three Point Bending ◽  
Ccd Detector ◽  
The Matrix ◽  
Dimensional Distribution ◽  
X Ray Computed ◽  
Synchrotron Microtomography

AbstractX-ray computed tomography (CT) uses absorption profiles from many different viewing directions to reconstruct the two-dimensional distribution of x-ray absorptivity within a slice of the sample. The tunability, high brightness and parallelism of synchrotron radiation are critical to high resolution (0.001mm), high contrast (1%) CT or microtomography. In situ study of samples multiple times during the course of an experiment is exciting to consider.Continuous fiber SiC/Al composites were deformed under three-point bending, and the resulting damage and fiber arrangement were revealed with synchrotron microtomography. Several hundred slices of 0.012 mm thickness were recorded simultaneously using 25 key radiation and a phosphor screen/charge coupled device (CCD) detector. Reconstruction was with the filtered back projection method. Low density regions were observed in the matrix in regions of highest stress where cracking is expected.

Stripping of Cosmic Spike Spectral Artifacts Using a New Upper-Bound Spectrum Algorithm

2001 ◽  
Vol 55 (11) ◽  
pp. 1523-1531 ◽  
Author(s):  
Dongmao Zhang ◽  
Karim N. Jallad ◽  
Dor Ben-Amotz
Keyword(s):  
Upper Bound ◽  
Band Intensity ◽  
Noise Filtering ◽  
Spectral Distortion ◽  
Charge Coupled Device ◽  
Background Fluorescence ◽  
Ccd Detector ◽  
A Charge ◽  
Induced Changes

A new upper-bound spectrum (UBS) method for removal of cosmic spike artifacts from spectra or images collected using a charge-coupled device (CCD) detector is proposed. This algorithm, which is shown to outperform previous methods, relies on an upper-bound spectrum, derived from scaled copies of consecutively collected spectra, which serves as a threshold for the detection of suspected cosmic spikes. Detected spikes are removed by replacement with the corresponding points in other spectra. Thus, unlike other commonly used methods, the UBS algorithm requires no smoothing or noise filtering and more reliably removes cosmic spikes of all magnitudes while introducing far less (if any) spectral distortion. The UBS method is tested using both synthetic and experimental (gypsum and gypsum/hematite mixture) spectra containing variable background (fluorescence), noise, and cosmic spike interference. The UBS method may in rare instances mistakenly identify spectral noise or photo-induced changes in band intensity (or shape) as cosmic spikes. However, as demonstrated through the use of both synthetic and experimental examples, such misidentifications produce little or no spectral distortion or artifacts in the resulting cosmic-spike-free output spectra.

Electronic excitation in symmetric ion–atom collisions: Kr+ + Kr

1980 ◽  
Vol 58 (10) ◽  
pp. 1518-1523 ◽  
Author(s):  
E. Grant Jones
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Electronic Excitation ◽  
Potential Energy Curve ◽  
Energy Curve ◽  
Translational Energy ◽  
Collisional Excitation ◽  
Short Range Interaction ◽  
Range Interaction ◽  
Curve Crossing

Cross sections are reported for reactions of Kr+ with Kr at collision energies below 50 eV (cm) to excite the KrI resonance radiation from the 5s[3/2]10 and 5s′[1/2]10 levels. Reaction occurs by the transfer of translational energy into internal energy and each reaction is characterized by a kinetic energy threshold. Significant effects on the cross section are observed arising from variation of the J-state of the reacting Kr+ beam. The reactions are interpreted as collisional excitation occurring by means of a potential energy curve crossing in the short-range interaction region.

Luminescence of Diatomic Molecular Ions

1971 ◽  
Vol 26 (12) ◽  
pp. 1998-2007
Author(s):  
F. J. Comes ◽  
F. Speier
Keyword(s):  
Cross Sections ◽  
Vibrational Energy ◽  
Ionic Species ◽  
Electronic Energy ◽  
Molecular Ions ◽  
Vibrational Quantum Number ◽  
Radiationless Transition ◽  
Parent Molecule ◽  
Condon Factors ◽  
Franck Condon

The ionic species N2+ B, CO+ A, CO+ B, and O2+ b have been produced by irradiation with the He I resonance line. Franck-Condon-factors both for excitation and deexcitation have been deduced from the fluorescence of the molecular ions. Most of them agree with calculated values of the Franck-Condon-factors. Measurements at different pressures ranging from 0.005 to 5 Torr lead to the deactivation cross sections for collisions with the parent molecule. N2+B also is deactivated in collisions with O2. Cross sections vary between 50 Å2 and 250 Å2 depending upon the ionic species and its vibrational quantum number. The deexcitation is described as a radiationless transition where electronic energy is transfered into vibrational energy

Appllied Crystallography in the Scanning Electron Microscope Using a CCD Detector*

1994 ◽  
Vol 38 ◽  
pp. 539-545 ◽  
Author(s):  
R.R. Goehner ◽  
J.R. Michael
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Lattice Parameter ◽  
Crystallographic Analysis ◽  
X Ray Diffraction ◽  
Charge Coupled Device ◽  
Backscattered Electrons ◽  
Ccd Detector ◽  
Backscattered Electron ◽  
Scanning Electron

Abstract The development of a new charge coupled device (CCD)-based detector for the scanning electron microscope (SEM) has allowed high quality backscattered electron Kikuchi patterns (BEKP) suitable for crystallographic analysis to be collected. These BEKPs can be used for crystallographic texture, phase and microstress analysis. This CCD detector system, can also be equipped with a special filter for removing backscattered electrons, which allows us to image low intensity, highly divergent x-ray diffraction (Kossel) patterns. The Kossel patterns are utilized for the accurate measurement of d-spacings suitable foe residual stress and lattice parameter measurements.

Spectra of zinc tetrabenzporphyrin in n-octane

1976 ◽  
Vol 29 (5) ◽  
pp. 933 ◽  
Author(s):  
PE Fielding ◽  
AWH Mau
Keyword(s):  
Excited States ◽  
Energy Surface ◽  
Soret Band ◽  
Relative Magnitude ◽  
Host Matrix ◽  
Solvent Interaction ◽  
Band Emission ◽  
Hot Band ◽  
Franck Condon ◽  
Surface Minima

A detailed spectroscopic study of zinc tetrabenzporphyrin in n-octane reveals the following: (i) the relative magnitude of solute-solvent interaction in the ground and excited states increases in the order T1 < S0 < S1 < S2. (ii) The potential energy surface minima of the ground and excited states are very similar within the framework of the Franck-Condon principle. (iii) The absence of any hot-band emission from the Q band (S1) and any emission from the Soret band (S2) indicates that significant amounts of energy degrade to the lowest vibrational level of S1. (iv) An earlier report on monomer phosphorescence is mainly due to aggregation. Selective narrow-band excitation is shown to be a useful technique to unravel complex spectra of porphyrins in Shpolskii-type matrices. Accurate measurements can be made of the energies for electronic transitions between the ground and excited states of molecules isolated in the various sites of the host matrix. The intensity ratios for electronic and vibronic bands can also be determined.

The X (X = F, Cl, I) effect on the photoassociation of H+X→HX

2015 ◽  
Vol 14 (08) ◽  
pp. 1550062
Author(s):  
Wei Gao ◽  
Bin-Bin Wang ◽  
Yong-Chang Han ◽  
Shu-Lin Cong
Keyword(s):  
Schrödinger Equation ◽  
Vibrational Level ◽  
Ground State ◽  
Schrodinger Equation ◽  
Vibrational State ◽  
Time Dependent ◽  
Overlap Integral ◽  
Target State ◽  
Multiphoton Transition ◽  
Franck Condon

This work explores the vibrational state-selective photoassociation (PA) in the ground state of the HX (X = F, Cl, I) molecule by solving the time-dependent Schrödinger equation. For the three systems, the vibrational level of [Formula: see text] is set to be the target state and the PA probability of the target state is calculated and compared by considering different initial collision momentums. It is found that the PA probabilities are in accordance with Franck–Condon overlap integral for the HI and HCl systems, but it is not the case for the HF system. Moreover, for the HF system, it is shown that the PA probability of the target state is largest and the multiphoton transition is more likely to occur.

Quantitative Investigation of Charge-Trapping Effects on Raman Spectra Acquired Using Charge-Coupled-Device (CCD) Detectors

1991 ◽  
Vol 45 (10) ◽  
pp. 1598-1603 ◽  
Author(s):  
W. B. Lacy ◽  
K. L. Rowlen ◽  
J. M. Harris
Keyword(s):  
Spectral Band ◽  
Charge Trapping ◽  
Light Level ◽  
Center Frequency ◽  
Integration Time ◽  
Spectral Parameters ◽  
Charge Coupled Device ◽  
Ccd Detector ◽  
Practical Guidelines ◽  
Ccd Detectors

Changes in spectral band parameters (width, center frequency, intensity) which arise from charge-trapping artifacts in the Thomson TH 7882 charge-coupled-device (CCD) detector are reported. These parameters are measured for a Raman scattering band of carbon tetrachloride with respect to CCD geometry (parallel vs. serial binning), in the presence and absence of preflash, vs. changes in integration time (variation in detected light level). The dependence of the spectral parameters on detector temperature was also measured. The degree of charge trapping and the charge transfer efficiency were estimated from the change in peak width and intensity vs. integration time, respectively, and were found to vary with detector temperature according to an Arrhenius relationship for the serial-binning geometry; from these results, the energy barriers to charge trapping and loss in the serial register were estimated. Practical guidelines for acquisition of binned spectra with this detector are suggested.

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