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111.
V. M. Naumenko 《International Journal of Infrared and Millimeter Waves》1981,2(1):149-158
Interaction of host magnons with impurity magnetic excitations in antiferromagnetic crystals CoCO3 and CoF2 containing substitutional impurity amounting to 10–4 and (4±2)×10–3 (by weight) Mn2+ respectively, has been investigated in the wavelength range 0.35–0.8 mm in a magnetic field of up to 20 T. In the CoCO3+10–4 Mn2+ crystal the impurity line was observed to merge with the AFMR line, which is peculiar to incoherent spectrum rearrangement. In the CoF2+4×10–3 Mn2+ crystal the cross splitting of spectrum was revealed as the impurity lower lying Zeeman level approached the AFMR low frequency mode, peculiar to coherent spectrum rearrangement. In both cases the impurity line intensity increases very much as it approaches the spin-wave band of the crystal. The constant of resonance interaction of the impurity excitation with magnons is determined for CoF2+Mn2+ to be m=18 cm–1. 相似文献
112.
Five two-photon excitable dipyrrylmetheneboron difluoride labels (dipyrrylmethene-BF2 labels) with fluorescence emission maximum between 530 and 590 nm, and a frequently used rhodamine label, TAMRA, were conjugated to aminomodified oligonucleotides. The performance of the labeled oligonucleotides was studied in a separation-free nucleic acid hybridization assay using ArcDia™ TPX bioaffinity assay technology. The results show that oligonucleotide conjugates of dipyrrylmethene-BF2 labels provide higher two-photon excited fluorescence yield and better assay sensitivity than corresponding TAMRA conjugate. The effect of conjugation on photophysical properties of the labels and performance of the labeled oligonucleotides in separation-free hybridization assay is discussed. 相似文献
113.
T.?A.?Prokof’evEmail author B.?A.?Polezhaev A.?V.?Kovalenko 《Journal of Applied Spectroscopy》2005,72(6):865-871
The mechanisms of photoluminescence excitation of Mn2+ ions in ZnS crystals have been investigated on the basis of complex analysis of the temperature dependences of the photoluminescence
and photoluminescence-excitation spectra of ZnS:Mn crystals. The activation energy of a manganese luminescence center was
estimated at Ea = 0.17 ± 0.05 eV. It is shown that Ea represents an energy band with a width ΔEa = 0.1 eV, within which a manganese luminescence center can experience radiationless recombination.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 788–793, November–December, 2005. 相似文献
114.
Epstein CL 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2004,167(2):399-210
This paper considers a variety of problems in the design of selective RF-pulses. We apply a formula of Zakharov and Manakov to directly relate the energy of an RF-envelope to the magnetization profile and certain auxiliary parameters used in the inverse scattering transform (IST) approach to RF-pulse synthesis. This allows a determination of the minimum possible energy for a given magnetization profile. We give an algorithm to construct both the minimum energy RF-envelope as well as any other envelope that produces a given magnetization profile. This includes an algorithm for solving the Gel'fand-Levitan-Marchenko equations with bound states. The SLR method is analyzed in terms of traditional scattering data, and shown to be a special (singular) case of the IST approach. RF-envelopes are computed for a variety of examples. 相似文献
115.
We describe a new experiment for measuring homonuclear-decoupled anisotropic chemical shift patterns in doubly 13C-labeled compounds under magic-angle spinning. The experiment combines a pair of selective and non-selective 180 degrees pulses to suppress the 13C-13C scalar and dipolar interactions. This is combined with the recently developed SUPER technique to recouple the chemical shift anisotropy. Demonstrations on 13Calpha and 13CO-labeled amino acids and peptides show that accurate chemical shift powder patterns can be obtained. This permits the use of chemical shift anisotropy for conformational studies of suitably extensively 13C-labeled peptides and proteins. 相似文献
116.
对基于双光子激发(TPE)的荧光相关谱(FCS)分析的理论公式进行了修正,引入了光漂白修正因子(θ)。修正公式不仅消除了光漂白因素对粒子动态信息测量结果的影响,而且还可以同时获得光漂白寿命。分别采用修正公式和原公式拟合了蔗糖溶液中若丹明(RB)的实验结果。结果表明:修正公式能够更好地定量描述实验结果,并且可以获得不同激发条件下的光漂白寿命。 相似文献
117.
T.?KunertEmail author R.?Schmidt 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,25(1):15-24
In Rydberg atoms subject to static and harmonic collinear electric fields, intrashell transition can be induced by the first
order perturbation from a small perpendicular electric or magnetic field, or by effects of the second order in the major fields.
Both mechanisms lead to resonances that are suppressed under certain conditions, and high-frequency interference oscillations
in case of non-adiabatic field switching. Recent measurements of microwave ionization signals show very rich and fascinating
structures similar to the ones predicted for intrashell mixing. We show that the observed ionization structures may be explained
by diabatic electric-field ionization and the consistent use of perturbation theory for intrashell mixing. In particular,
the dominant oscillation frequency is successfully interpreted in terms of interference between first and second order transition
amplitudes. New predictions are provided. The present approach gives a comprehensive picture of intrashell transitions, which
may be tested in future experiments designed to observe such transitions directly.
Received 2 May 2002 / Received in final form 23 September 2002 Published online 21 January 2003
RID="a"
ID="a"e-mail: Valentin.Ostrovsky@pobox.spbu.ru
RID="b"
ID="b"e-mail: horsdal@ifa.au.dk 相似文献
118.
A. Gopalan J. Bömmels S. Götte A. Landwehr K. Franz M.-W. Ruf H. Hotop K. Bartschat 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(1):17-29
A novel electron scattering apparatus for high resolution studies of angle-differential elastic and inelastic electron scattering
from atoms and molecules in the gas phase is described and its performance characterized. It combines a laser photoelectron
source, a triply differentially pumped collimated supersonic beam target (half angle 0.015 rad, background to beam density
ratio < 0.01), and several electron multipliers for simultaneous detection of elastically scattered electrons and metastable atoms (or
molecules) due to inelastic scattering. In detailed test measurements of the yield for the production of metastable He*(23S1) atoms around its threshold, the dependence of the overall energy width on various experimental parameters has been investigated.
So far a resolution down to 7 meV (FWHM) has been obtained. Under such conditions we have investigated the profile of the
He- (1
s
2
s
2
2
S
1/2
) resonance at the scattering angles 22
°
, 45
°
, and 90
°
. From a consistent fit of the measured profiles by resonant scattering theory we determine a new value for the resonance
energy ( E
r
= 19.365(1) eV) and an accurate resonance width ( Γ = 11.2(5) meV). These results are consistent with the previously recommended values.
Received 23 July 2002 Published online 29 October 2002
RID="a"
ID="a"e-mail: hotop@physik.uni-kl.de
RID="b"
ID="b"Permanent address: Department of Physics and Astronomy, Drake University, Des Moines, IA 50311, USA. 相似文献
119.
M. Fifirig A. Cionga F. Ehlotzky 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(3):333-336
The two-photon ionization of the hydrogen atom from its ground state by a two-colour electromagnetic field consisting of two
odd harmonics of the same IR laser is analyzed. The influence of the state of polarization of the bichromatic field on the
azimuthal angular distribution and the dependence of the elliptic dichroism on the photon frequencies are reported.
Received 11 December 2002 Published online 29 April 2003
RID="a"
ID="a"e-mail: fritz.ehlotzky@uibk.ac.at 相似文献
120.
K.N. Joshipura M. Vinodkumar B.K. Antony N.J. Mason 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(1):81-90
Total ionization cross-sections of electron impact are calculated for the molecular targets CHx, CFx, SiHx, SiFx (x = 1-4) and CCl4 at incident energies 20-3 000 eV. The calculation is based on Complex Scattering Potential approach, as developed by us recently.
This leads to total inelastic cross-sections, from which the total ionization cross-sections are extracted by reasonable physical arguments. Extensive comparisons are made here with the previous theoretical
and experimental data. The present results are satisfactory except for the CFx and SiFx (x = 1-3) radicals, for which the experimental data are lower than most of the theories by more than 50%.
Received 23 May 2002 / Received in final form 24 October 2002 Published online 21 January 2003
RID="a"
ID="a"e-mail: knjoshipura@yahoo.com 相似文献