共查询到20条相似文献,搜索用时 62 毫秒
1.
J.D. Petke Gerald M. Maggiora Lester L. Shipman Ralph E. Christoffersen 《Journal of Molecular Spectroscopy》1978,73(2):311-331
Ab initio configuration interaction wavefunctions and energies are reported for the ground state and many low-lying singlet and triplet states of magnesium chlorin and chlorin, and are employed in an analysis of the electronic absorption spectra of these systems.In chlorin, the calculated visible spectrum consists of two states, the lower energy, y-polarized state exhibiting moderate absorption intensity in contrast to the very weak absorption of the higher energy x-polarized state. The configurational composition of both states is well described by the four-orbital model. Five states are responsible for the Soret band envelope. A moderately intense y-state lies under the low energy edge of the band envelope, while two x-polarized states of moderate and strong intensity, respectively, are responsible for the band maximum. The final two states lie at the high energy edge of the Soret band and introduce a measure of asymmetry into the band envelope. Two states of very weak oscillator strength are also found in this region of the spectrum. All the Soret states are of complex configurational composition, and several of the higher lying states contain contributions from doubly excited configurations.The calculated visible spectrum of magnesium chlorin also consists of two states, with the weakly absorbing x-polarized state lying approximately 200 cm?1 lower in energy than the moderately intense y-polarized state. The configurational composition of both states is well described by the four-orbital model. Four states constitute the bulk of the intensity in the Soret band envelope. In distinction to chlorin, the moderately intense state at the low energy edge of the band envelope is x-polarized. Two intense states of y- and x-polarization, respectively, constitute the band maximum region, and a single x-polarized state of moderately strong intensity can be assigned to the high energy shoulder of the band envelope. Two other weakly absorbing states are also found in this region, along with another weakly absorbing state of mixed in-plane and out-of-plane polarization. No clearly defined states are observed. As was the case for chlorin, all the Soret states are of complex configurational composition, and some of the higher energy states contain significant contributions from doubly excited configurations.Chlorin and magnesium chlorin both possess three states which lie below S1 and a single which lies slightly above S2. All four of the low-lying states in each molecule are well described by the four-orbital model, with T1 being essentially a single configuration in each case. The remainder of the states are clustered in the same energetic region as the comparable Soret states, with comparably complex configurational compositions.Dipole moments and charge distributions for low-lying singlet and triplet states are also reported, and are used to rationalize chemical reactivity characteristics. 相似文献
2.
An interesting type of 2-step reaction is that illustrated by , i.e., a direct reaction to a resonant final state , which subsequently decays. We are especially interested in the situation in which the resonances are sufficiently dense in energy that they overlap, Γ > D, and we present a formalism for calculating the energy-averaged fluctuation cross section to any of the final channels (c + C). In particular, its application to the case in which the states are modulated by a doorway, (e.g., an isobaric analog state with fine structure) is worked out in some detail. 相似文献
3.
The results of measurements for pentane solutions of o-nitrotoluene near their critical temperature are presented. The value for the critical solution (f=0.36) is positive and greater than for pure o-nitrotoluene, which is attributed to the interaction of concentration fluctuations with the electric field. 相似文献
4.
W. Morris B.Y. Oh D.L. Parker G.A. Smith J. Whitmore L. Voyvodic R. Walker R. Yaari E.W. Anderson H.B. Crawley W.J. Kernan F. Ogino R.G. Glasser D.G. Hill G. McClellan H.L. Price B. Sechi-Zorn G.A. Snow V.P. Kenney 《Physics letters. [Part B]》1975,56(4):395-399
Using new data from 100 interactions, we find the energy dependence of the invariant cross-section in the target fragmentation (central) region to be consistent with an behavior. The leading particle peak near x = + 1 exhibits a width in x which becomes smaller with increasing energy and an integrated cross section which is approximately energy independent. 相似文献
5.
G.M. Lawrence S.C. Seitel 《Journal of Quantitative Spectroscopy & Radiative Transfer》1973,13(8):713-716
Relative oscillator strengths in the Cameron system of CO(a3Π ← X1Σ) have been observed in absorption for six bands (υ′ = 0–5, υ″ = 0) with the result, normalized to the absolute (0, 0) band measurement of Hasson and Nicholls, , , , , , . The density of CO was modulated with a motor-driven vacuum valve and synchronous fluctuations (?1 per cent) in the transmitted intensity detected with a lock-in amplifier. Peak pressure in the 21 cm absorption cell was approximately 10 torr. A curve of growth analysis was used to correct saturation effects by less than 3 per cent. 相似文献
6.
G.T.A. Squier W.E. Burcham S.D. Hoath J.M. Freeman P.H. Barker R.J. Petty 《Physics letters. [Part B]》1976,65(2):122-124
The reaction threshold has been measured as 8007.7 ± 1.8 keV, equivalent to an energy release of 6030.6 ± 1.8 keV in the beta decay. The half-life has been measured as 422.28 + 0.23 ms. The corresponding ft value is reasonably consistent with those of other superallowed Fermi decays. 相似文献
7.
H.G. Kirk R. Schulte P. Sixel M. Klein M. Walter M.J. Counihan D.J. Kocher P. Kostka P.K. Malhotra D.R.O. Morrison H. Saarikko K.L. Wernhard K.W.J. Barnham R.M. Eason D.P. Dallman F. Mandl M. Markytan 《Nuclear Physics B》1976,116(1):99-117
The inclusive production of K?1(890) and K?1(1420) is studied in K??p interactions at 10 and 16 GeV/c. At 10 GeV/c an enhancement in the () mass distribution is found at 1.74 GeV, but no clear signal is seen at 16 GeV/c. The fraction of coming from decay of the is large, being (50 ± 6)% and (45 ± 5)% at 10 and 16 GeV/c, respectively. The inclusive cross sections for K1?(890) and production are almost constant with energy from 8 to 32 GeV/c with values of 3.5 and 3.3 mb, respectively. The production cross section is studied as a function of transverse and longitudinal variables and found to derive mainly from fragmentation of the incident K? meson. The spectra of resulting from the decay of are studied. 相似文献
8.
Compound nucleus states in and have been investigated with the and three-particle reactions. The observed states (EX≈20 MeV) can be understood, in analogy to the ground states of the A=5 system, by coupling a nucleon to the first 0+ excited state of . 相似文献
9.
P. Exner 《Reports on Mathematical Physics》1984,19(2):249-255
An extensive set of inequalities is derived for (ψ,?ψ) in which contains the Bargmann inequalities as a special case. 相似文献
10.
The structure factor is calculated for a Bose fluid using an expression for S(k), which is approximately valid for all values of k. Marked fluctuations appear for , near the roton dip in Ek, and at near the dip in the second branch of Ek. Our calculations are indirectly a theoretical justification for the existence of a second branch in Ek. The results presented here agree fairly well with the experimental values for along with a dip at which has not been reported earlier. It also suggests the existence of two waves, phonons and rotons, for . 相似文献
11.
The vibration-rotation transitions for v = 1 ← 0 of NO () have been studied by using the technique of laser magnetic resonance spectroscopy. Five magnetic resonance lines are observed with three CO laser lines in the range from 1859 to 1886 cm?1. From these, three zero-field transition frequencies, v = 1 ← 0; , , and are obtained with an accuracy of ±0.0007 cm?1. The molecular constants which have been determined by borrowing centrifugal constants from a previous infrared work are , , and . 相似文献
12.
E. Iguchi 《Journal of Physics and Chemistry of Solids》1977,38(9):1039-1045
The displacements of non-parallel {102} CS planes in slightly reduced WO3 observed by electron microscopy were quantified with the theory of elasticity for an isotropic continum. By this calculation, the magnitude of the force between cations in CS planes was estimated. It was found that the principle force involved was an attractive one between cations in the CS plane which was calculated to be . Using this value, the magnitude of the strain energy was also evaluated, and was found to be larger in value than the energy associated with the dissociation of oxygen atoms from WO3 lattice. This suggests that the strain energy plays a dominant role in the behaviour of CS planes. 相似文献
13.
We have obtained a least upper bound, , on the critical temperature Tc of an isotropic superconductor with paramagnetic impurities described by the scattering matrix t for fixed values of μ1. We have also obtained the corresponding optimal spectrum . The numerical results for the functions are presented for and 0.16 in the form of universal curves representing as functions of the reduced impurity concentration . We have also established an upper limit to the reduced critical concentration for an arbitrary shape of α2F(ω)1. 相似文献
14.
Line positions and molecular constants for the 0-0, 1-0, 2-0, 0-1, 2-1, 3-1, 0-2, 1-2, and 4-2 bands of the C2 Phillips system () are reported. Among them, five bands have not been reported previously. Rotational perturbations have been observed in the previously unobserved v = 1 level of the state. This state is perturbed by the state which was discovered by Ballik and Ramsay. These observations provide new information regarding the perturbing state. In particular, the minimum of the potential energy for the state has been found to be at 9227.4 cm?1 instead of 13 310 cm?1, which was the previous Te value for this electronic state. 相似文献
15.
16.
Differential cross sections, vector and tensor analysing powers have been measured for the 61Ni(d, p) reaction at a deuteron energy of 12.3 MeV. Most of the 30 transitions observed below 8.5 MeV excitation are dominated by a single j-value, which was determined from behaviour of the analysing power data. For a number of transitions it was possible to make unambiguous j-assignment relying on the established j-dependence of the T22 tensor analysing power. The deduced spectroscopic factors indicate that the full strength of neutron transfer to the () and orbits was found and seven transitions were located above 5.3 MeV. The separated strengths of the transitions are compared with shell-model calculations for the low-lying states of 62Ni. 相似文献
17.
18.
An analytical expression is obtained for the binding energy of a neutral atom within the statistical theory , which prefectly reproduces SCF binding energy for Z > 20. The oscillations of energy are discussed. 相似文献
19.
J. Czerwonko 《Physica A》1980,100(2):291-306
Formal solutions for the autocorrelation functions of density and the transversal current are discussed in the acoustic and quasihomogeneous regime. The poles of these functions are obtained without any restrictions imposed on Landau parameters. The formula for sound dispersion at T = 0 is generalized by the inclusion of terms of the relative order of , (k is the wave vector, v is the Fermi velocity, Δ is the energy gap, ). The dispersion formulae for transversal and longitudinal excitations with a gap for 3He(B) are also given, with an accuracy up to the terms of the order of , for 0 ? T ? Tc, and without any restrictions imposed on Landau parameters. Under these last assumptions our autocorrelation functions are calculated in the polar as well as non-polar regions. It is shown that if T > 0, the transversal function vanishes at some ω, such that . Moreover,the zero of the density autocorrelation function is distanced from its pole by an amount of the order of . 相似文献
20.
S.D. Kouimtzi 《Solid State Communications》1985,55(5):447-450
A.c. conductivity is studied in n-type electron irradiated GaAs at helium temperatures. For T < 25 K variable range hopping is observed. The experimentally observed low values of are discussed. At T > 30 K the conductivity exhibits an activation energy of 0.5 meV which is attributed to excitation into an upper band. The frequency dependence of hopping conductance is σ ∝ ωS with S=1.8 and S=0.9 depending on the degree of radiation induced damage. 相似文献