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1.
Inelastic collisions of slow electrons with SrBr2 molecules were studied experimentally. The dissociative excitation cross sections of two lines of the strontium atom and eight lines of the singly charged strontium ion were measured. Six optical excitation functions were recorded over the electron energy range 0–100 eV. Dissociative excitation cross sections were also measured for two strontium monobromide sequences related to the B 2Σ+-X 2Σ+ system. 相似文献
2.
The dissociative excitation of singlet and quintet nickel atom states in e-NiBr2 collisions was studied by the method of extended intersecting beams. Optical excitation functions over the electron energy
range 0–100 eV were recorded for most of the spectral lines observed. Possible dissociative excitation channels at low electron
energies were discussed. The cross sections of dissociative and direct excitations and dissociative excitations of the NiBr2 and NiCl2 molecules were compared. 相似文献
3.
The cross sections of dissociative excitation of 46 transitions from cobalt atom even sextet levels in collisions of electrons with CoCl2 molecules were measured at an exciting electron energy of 100 eV. The dissociative and direct CoI excitation cross sections were compared. The results were used to calculate the total cross sections of dissociative excitation of CoI levels at an electron energy of 100 eV. Possible reaction channels at low electron energies are discussed. 相似文献
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5.
H. Cherkani-Hassani D. S. Belic J. J. Jureta J. Lecointre P. Defrance 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,58(1):85-94
Absolute cross-sections for electron-impact dissociative ionization of C2
H2+ and C2 D2+ to CH+, C+, C2+ , H+, CH2+
and C2D+ fragments are determined for electron energies ranging
from the corresponding threshold to 2.5 keV. Results obtained in a crossed
beams experiment are analyzed to estimate the contribution of dissociative
ionization to each fragment formation. The dissociative ionization cross
sections are seen to decrease for more than an order of magnitude, from
CH+ (5.37±0.10) × 10-17 cm2 over C+ (4.19±
0.16) × 10-17 cm2, C2D+ (3.94±0.38) ×
10-17 cm2, C2+ (3.82±0.15) × 10-17 cm2
and H+ (3.37±0.21) × 10-17 cm2 to CH2+
(2.66±0.14) × 10-18 cm2. Kinetic energy release
distributions of fragment ions are also determined from the analysis of the
product velocity distribution. Cross section values, threshold energies and
kinetic energies are compared with the data available from the literature.
Conforming to the scheme used in the study of the dissociative excitation of
C2H2+
( C2 D2+ )\left( {\rm C}_2 {\rm D}_2^+ \right), the cross-sections are presented in
a format suitable for their implementation in plasma simulation codes. 相似文献
6.
E. I. Nedrigaylov V. V. Styrov 《Bulletin of the Russian Academy of Sciences: Physics》2008,72(7):899-901
It is shown that the CO + O2 → CO2 catalytic reaction on the surface of Y2O3-Eu may lead to electronic excitation of Eu3+ luminescence centers due to the chemical energy release. The luminescence observed allows one to study the interaction between
molecular particles of ultralow (thermal) energies with surface by optical methods. 相似文献
7.
The extended crossed beam method was used to measure the dissociative excitation cross sections in e-CoCl2 collisions for 91 transitions from odd doublet levels of cobalt atoms. The dissociative and direct CoI excitation cross sections
were compared. Possible reaction channels at low electron energies were considered. The results were used to calculate the
total dissociative excitation cross section of CoI levels at an exciting electron energy of 100 eV. For the z
2
F°, z
2
G°, and y
2
G° levels, cascade population contributions were also determined. 相似文献
8.
The initiation of H2/O2/H2O mixture combustion when asymmetric vibrations in H2O molecules are excited by a resonant IR laser radiation is considered. It is shown that the vibrational excitation of the molecules gives rise to new efficient channels for the formation of chemically active O and H atoms and OH radicals. As a result, the chain mechanism of combustion in the mixtures is enhanced and, as a consequence, the induction time is cut and the ignition temperature is lowered. Even at a minor radiant energy flux delivered to the gas (Ein≈2.5 J/cm2), the ignition temperature of the stoichiometric H2/O2 mixture containing only 5% of H2O may become as low as 300 K. 相似文献
9.
Inelastic collisions of electrons with manganese dibromide molecules were studied by the method of extended crossing beams.
These collisions cause the formation of excited manganese atoms in doublet and sextet states. At an exciting electron energy
of 100 eV, 52 dissociative excitation cross sections were measured. At electron energies 0–100 eV, three optical excitation
functions were recorded. The ratio between excitation cross sections in electron-molecular and electron-atomic collisions
is considered. 相似文献
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11.
B. H. Yang P. C. Stancil 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(3):351-358
Quantum close-coupling and coupled-states approximation
scattering calculations for rotational energy transfer
of rotationally excited NH3 and ND3 due to collisions with He
are presented. Calculations were performed for collision
energies between 10-5 and 10 000 cm-1
using the NH3-He potential of Hodges and Wheatley [J. Chem. Phys.
114, 8836 (2001)]. State-to-state and total quenching cross sections from
some selected initial states are presented.
Rate coefficients for ortho-NH3 for the quenching 10+→00+
transition were obtained on potentials scaled to reproduce measurements
of second virial coefficients with the results showing strong sensitivity
to the potential, especially at low temperatures. Significant isotope
effects are found in quenching cross sections in the cold to ultracold
regime particularly in the region dominated by quasi-bound resonances,
~0.1 to 10 cm-1. As ammonia has been translationally cooled
via Stark deceleration methods, it is a good candidate for experimental
study of such effects at cold temperatures.
Comparison of rate coefficients with available theoretical results
are also presented. 相似文献
12.
D. Hennequin P. Verkerk 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,57(1):95-104
The dynamics of cold atoms in conservative optical lattices obviously depends on the geometry of the lattice. But very similar
lattices may lead to deeply different dynamics. In a 2D optical lattice with a square mesh, it is expected that the coupling
between the degrees of freedom leads to chaotic motions. However, in some conditions, chaos remains marginal. The aim of this
paper is to understand the dynamical mechanisms inhibiting the appearance of chaos in such a case. As the quantum dynamics
of a system is defined as a function of its classical dynamics – e.g. quantum chaos is defined as the quantum regime of a
system whose classical dynamics is chaotic – we focus here on the dynamical regimes of classical atoms inside a well. We show
that when chaos is inhibited, the motions in the two directions of space are frequency locked in most of the phase space,
for most of the parameters of the lattice and atoms. This synchronization, not as strict as that of a dissipative system,
is nevertheless a mechanism powerful enough to explain that chaos cannot appear in such conditions. 相似文献
13.
Excitation of H+, H2
+, H3
+, He+, and Ar+ ions by
impact on graphite and Al2O3 was investigated by means of emission
spectroscopy in the 50–1000 eV energy range of the projectiles.
Emission of Balmer series from excited neutral hydrogen is
observed for both targets. In addition, for the Al2O3 target
a continuum emission is observed. The continuum probably originates
from excited MnOm molecules produced in the collision cascade, when
surface atoms bound by ionic bonds are released after the bond breaking
caused by neutralization. The spectra obtained under Ar+ -bombardment
show Ar II lines emitted by backscattered ions. 相似文献
14.
15.
Processes of electronic excitation energy transfer (EEET) in H2O+D2O solutions within reversed micelles with different degrees of hydration were studied. It is ascertained that the structure of solutions forms a cluster distribution of interacting molecules having a fractal dimensionality. As a result, in regions with a locally high concentration of the dye molecules, an increase in the EEET efficiency is observed. Solubilization by reversed micelles leads to destruction of the cluster structure of the water system, with the dependence of the EEET efficiency on the degree of hydration being nonmonotonic. As the degree of hydration increases, the inhomogeneities of the structure inherent in bulk water are restored. 相似文献
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18.
Structures of H2CN and CH2CN molecules are similar to that of H2CO molecule. The H2CO has shown anomalous absorption for its transition 111–110 at 4.8 GHz in a number of cool molecular clouds. Though the molecules H2CN and CH2CN have been identified in TMC-1 and Sgr B2 through some transitions in ortho as well as in para species, here we have investigated
the condition under which transitions 111–110 and 212–211 of these molecules may show anomalous absorption.
For the present investigation, we have calculated energy levels and radiative transition probabilities. However, we have used
scaled values for collisional rate coefficients. We found that relative values of collisional rate coefficients can produce
the required anom-alous absorption in 111–110 and 212–211 transitions in the molecules.
相似文献
19.
M. A. Buldakov B. V. Korolev I. I. Matrosov V. N. Cherepanov 《Optics and Spectroscopy》2003,94(2):185-190
In the context of the Silberstein theory, by introducing model atoms, the polarizability of pairs of interacting molecules N2-N2, O2-O2, and N2-O2 was studied in relation to the mutual orientation and the intermolecular distance of the molecules in the pairs. The polarizability tensor for the equilibrium configurations of the (N2)2 and (O2)2 dimers was calculated. 相似文献
20.
Y. M. Smirnov 《Journal of Applied Spectroscopy》1998,65(2):161-167
Dissociation-induced excitation of a singly charged cesium ion taking place as a result of collisions of electrons with CsOH
molecules is investigated. Possible reaction channels in the low-energy region are discussed. It is established that sequential
population plays an important role for 6p levels of Cs+.
Moscow Power Engineering Institute, 14, Krasnokazarmennaya St., Moscow, 111250, Russia. Translated from Zhurnal Prikladnoi
Spektroskopii, Vol. 65, No. 2, pp. 159–165, March–April, 1998. 相似文献