Hanle effect in the singlet excited states of the alkaline earths

1980 ◽  
Vol 58 (10) ◽  
pp. 1416-1419 ◽  
Author(s):  
F. M. Kelly ◽  
M. S. Mathur
Keyword(s):  
Excited States ◽  
Cross Sections ◽  
Ground Level ◽  
High Density ◽  
Oscillator Strengths ◽  
Low Density ◽  
Density Data ◽  
Hanle Effect ◽  
Singlet States ◽  
Alkaline Earths

The Hanle effect in the singlet states of Sr, Ba, Mg, and Ca has been studied over a range of densities. The low density observations lead to an accurate lifetime measurement of the singlet excited levels, and calculation of the related oscillator strengths. The depolarization cross sections, [Formula: see text], for collision with ground level neutral atoms have been obtained from the high density data.

The density dependence of the Hanle effect in the resonance line of atomic barium

1977 ◽  
Vol 55 (1) ◽  
pp. 83-91 ◽  
Author(s):  
F. M. Kelly ◽  
M. S. Mathur
Keyword(s):  
Cross Sections ◽  
Resonance Line ◽  
Excited Level ◽  
Ground Level ◽  
Multipole Moment ◽  
Low Density ◽  
Density Region ◽  
Hanle Effect ◽  
Wide Range ◽  
Theoretical Predictions

The change in the Hanle effect of the singlet resonance line of neutral barium has been studied over a wide range of density. The low density region has been used to confirm a lifetime of 8.37 ± 0.08 ns for the 6s6p1P1 level. We have determined the cross sections for the relaxation of the multipole moment of order 2 for collisions of the excited level with the ground level and with the metastable 6s5d1D2 level, and comparisons are made with the measured value of [Formula: see text] for the ground level with theoretical predictions.

Density dependence of the Hanle effect of the 3s4p1P10 level of neutral magnesium

1979 ◽  
Vol 57 (6) ◽  
pp. 838-840
Author(s):  
F. M. Kelly ◽  
M. S. Mathur
Keyword(s):  
Density Dependence ◽  
Excited Level ◽  
Lifetime Measurement ◽  
Oscillator Strengths ◽  
Low Density ◽  
Hanle Effect

The Hanle effect in the 3s2 1S0–3s4p1P1 (2026 Å) transition of Mg I has been studied over a range of densities. The low density observations lead to an accurate lifetime measurement of the 4p1P1 excited level. Related oscillator strengths are calculated.

scholarly journals Electron Impact Excitation Cross Sections for B III

1983 ◽  
Vol 36 (5) ◽  
pp. 659
Author(s):  
PS Ganas ◽  
M Aryafar ◽  
LP Gately
Keyword(s):  
Electron Impact ◽  
Excited States ◽  
Cross Sections ◽  
Born Approximation ◽  
Oscillator Strengths ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Central Potential ◽  
Excitation Cross Sections ◽  
Generalized Oscillator

A realistic analytical central potential with two adjustable parameters is used to generate wavefunctions for the ground and excited states of doubly ionized boron. Generalized oscillator strengths and integrated cross sections from threshold up to 5 keY are calculated in the Born approximation for 2s-ns, 2s-np and 2s-nd excitations. Convenient analytic formulae for the cross sections are presented.

Optische Anregung beim Ladungsaustausch von Edelgasionen für Stoßenergien von 5 bis 300 eVolt

1968 ◽  
Vol 23 (7) ◽  
pp. 970-978
Author(s):  
H. Schlumbohm
Keyword(s):  
Charge Transfer ◽  
Kinetic Energy ◽  
Internal Energy ◽  
Excited States ◽  
Cross Sections ◽  
Ground Level ◽  
High Rate ◽  
Transfer Processes ◽  
The Cross ◽  
Threshold Energies

Measurements of the photoemission caused by collisions of ground level He+- and Ne+-ions with Ar- and Kr-atoms have shown several multipletts of Ar II and Kr II within the investigated wavelength range of 3500 to 5500 A. At a high rate the charge transfer processes occur into excited states of Ar* and Kr*. The reactions are endothermic with a deficit of internal energy between 6 and 19 eV.The cross sections measured for several chosen transitions start at characteristic threshold energies between 10 and 25 eV. Above the threshold the cross sections rise slowly with increasing energy when Ne* is the colliding ion and very fast for He+. Above 50 to 100 eV the cross sections show nearly constant values. — The minimum kinetic energy values are calculated, which can just fill up the deficits of internal energy, and are shown to be equal to the measured threshold energies. Thus it follows that the pseudo-crossing of the potential energy curves of the quasimolecules occurs at an energy value equal to the asymptotic level of the above curve.

Excited State Absorption and Cross Sections for Er-Doped Glasses

1989 ◽  
Vol 172 ◽  
Author(s):  
S. Zemon ◽  
G. Lambert ◽  
W. J. Miniscalco ◽  
L. J. Andrews ◽  
B. T. Hall
Keyword(s):  
Excited State ◽  
Excited States ◽  
Cross Sections ◽  
Ground State ◽  
Excited State Absorption ◽  
Fiber Amplifiers ◽  
Oscillator Strengths ◽  
Ground State Absorption ◽  
Doped Glasses ◽  
Er Doped

AbstractPump-excited-state-absorption (ESA) measurements on Er3+-doped phosphates, fluorophosphates, and silicate bulk glasses indicate that ESA cross sections are approximately equal to ground state absorption (GSA) cross sections in the 800-nm band. The oscillator strengths of the ESA and GSA bands are also approximately equal, in qualitative agreement with Judd-Ofelt calculations. Fluorozirconate samples were found to have substantial populations in the upper excited states for the measurement conditions used and ESA transitions originating from four excited states were identified. Fluorozirconate fiber amplifiers and lasers at 1.55 μm, therefore, would have decreased efficiency for 800-nm pumping.

scholarly journals COMPARISON OF HIGH AND LOW DENSITY AIRBORNE LIDAR DATA FOR FOREST ROAD QUALITY ASSESSMENT

2016 ◽  
Vol III-8 ◽  
pp. 167-172
Author(s):  
K. Kiss ◽  
J. Malinen ◽  
T. Tokola
Keyword(s):  
Laser Scanning ◽  
High Density ◽  
Road Surface ◽  
Airborne Laser Scanning ◽  
Low Density ◽  
Surface Wear ◽  
Forest Roads ◽  
Density Data ◽  
The Road ◽  
Airborne Laser

Good quality forest roads are important for forest management. Airborne laser scanning data can help create automatized road quality detection, thus avoiding field visits. Two different pulse density datasets have been used to assess road quality: high-density airborne laser scanning data from Kiihtelysvaara and low-density data from Tuusniemi, Finland. The field inventory mainly focused on the surface wear condition, structural condition, flatness, road side vegetation and drying of the road. Observations were divided into poor, satisfactory and good categories based on the current Finnish quality standards used for forest roads. Digital Elevation Models were derived from the laser point cloud, and indices were calculated to determine road quality. The calculated indices assessed the topographic differences on the road surface and road sides. The topographic position index works well in flat terrain only, while the standardized elevation index described the road surface better if the differences are bigger. Both indices require at least a 1 metre resolution. High-density data is necessary for analysis of the road surface, and the indices relate mostly to the surface wear and flatness. The classification was more precise (31–92%) than on low-density data (25–40%). However, ditch detection and classification can be carried out using the sparse dataset as well (with a success rate of 69%). The use of airborne laser scanning data can provide quality information on forest roads.

Density dependence of the Hanle effect of the 4s4p1P1 level of neutral calcium

1980 ◽  
Vol 58 (7) ◽  
pp. 1004-1009 ◽  
Author(s):  
F. M. Kelly ◽  
M. S. Mathur
Keyword(s):  
Density Dependence ◽  
High Density ◽  
Low Density ◽  
Density Region ◽  
Hanle Effect ◽  
Wide Range ◽  
High Density Region

The Hanle effect in the 4s21S0–4s4p1P1 (4226.7 Å) transition in Ca I has been observed over a wide range of densities. The low density observations determine the lifetime of the 1P1 level to be 4.49 ns. Collision parameters are obtained from observations in the high density region.

Excitation of lithium atoms by electron impact

1983 ◽  
Vol 61 (1) ◽  
pp. 1-5
Author(s):  
P. S. Ganas
Keyword(s):  
Experimental Data ◽  
Electron Impact ◽  
Excited States ◽  
Cross Sections ◽  
Born Approximation ◽  
Wave Functions ◽  
Oscillator Strengths ◽  
Central Potential ◽  
Generalized Oscillator ◽  
Comparison Of The Results

A realistic analytic central potential is used to generate wave functions for the ground and excited states of lithium. Generalized oscillator strengths and integrated cross sections from threshold up to 5 keV are calculated in the Born approximation for 2s–ns, 2s–np and 2s–nd excitations. Comparison of the results with experimental data is discussed.

Besetzungsdichten angeregter He l-Atome in einem nicht-thermischen Plasma

1964 ◽  
Vol 19 (13) ◽  
pp. 1451-1460 ◽  
Author(s):  
Hans-Werner Drawin
Keyword(s):  
Excited States ◽  
Cross Sections ◽  
Relaxation Times ◽  
Ground Level ◽  
Local Thermal Equilibrium ◽  
Rate Equations ◽  
Population Densities ◽  
Total Cross Sections ◽  
Lower Singlet ◽  
Thin Plasma

For nonthermal plasmas, the population densities of the ground level and the lower lying excited states can deviate considerably from a SAHA- and BOLTZMANN population density which are only valid for plasmas in (local) thermal equilibrium. To obtain the actual population densities of the lower lying- states of the He I-Atom in a nonthermal, optically thin as well as in a partially optically thick plasma the corresponding rate equations have been solved. Due to the metastable state 23S we have distinguished between the singulet and the triplet system. The coupling between the two systems has been accomplished by appropriate collisional processes. Numerical values are given for the population densities in terms of „SAHA“-population densities for both the lower singlet- and triplet levels in the case of an optically thin plasma. The relaxation times necessary for establishing a steadystate have been calculated. The influence of the triplet-system on the particle densities of the singletsystem is shown. For low electron densities the ratio ni (triplet) /ni (singlet) becomes larger than 3. By solving the complete system of rate equations and comparing the solutions with measured densities one can derive unknown total cross sections for reactions between excited states.

scholarly journals COMPARISON OF HIGH AND LOW DENSITY AIRBORNE LIDAR DATA FOR FOREST ROAD QUALITY ASSESSMENT

2016 ◽  
Vol III-8 ◽  
pp. 167-172 ◽  
Author(s):  
K. Kiss ◽  
J. Malinen ◽  
T. Tokola
Keyword(s):  
Laser Scanning ◽  
High Density ◽  
Road Surface ◽  
Airborne Laser Scanning ◽  
Low Density ◽  
Surface Wear ◽  
Forest Roads ◽  
Density Data ◽  
The Road ◽  
Airborne Laser

Good quality forest roads are important for forest management. Airborne laser scanning data can help create automatized road quality detection, thus avoiding field visits. Two different pulse density datasets have been used to assess road quality: high-density airborne laser scanning data from Kiihtelysvaara and low-density data from Tuusniemi, Finland. The field inventory mainly focused on the surface wear condition, structural condition, flatness, road side vegetation and drying of the road. Observations were divided into poor, satisfactory and good categories based on the current Finnish quality standards used for forest roads. Digital Elevation Models were derived from the laser point cloud, and indices were calculated to determine road quality. The calculated indices assessed the topographic differences on the road surface and road sides. The topographic position index works well in flat terrain only, while the standardized elevation index described the road surface better if the differences are bigger. Both indices require at least a 1 metre resolution. High-density data is necessary for analysis of the road surface, and the indices relate mostly to the surface wear and flatness. The classification was more precise (31–92%) than on low-density data (25–40%). However, ditch detection and classification can be carried out using the sparse dataset as well (with a success rate of 69%). The use of airborne laser scanning data can provide quality information on forest roads.

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