COLLECTIVE EXCITATION SPECTRA IN EVEN-EVEN DEFORMED NUCLEI Ⅲ.——VARIOUS EXPANSIONS OF EXCITATION ENERGY OF GROUND BAND

The expansions of the excitation energy of the ground band in even-even deformed nucleus are discussed in the framework of our expression deduced in the previous papers. The conventional I(I+1)-expansion which is applicable to the region of low angular momenta is obtained and its radius of convergence is estimated. It can be proved that the ω₁-expansion is always convergent and hence the empirical fact that the ω_I-expansion converges better than the I(I+1)-expansion is explained satisfactorily.     

SUq(2) Analysis of Nuclear Rotational Spectra

The validity of the quantum group SU_q(2) expression for the nuclear rotational spectrum is investigated thoroughly.Analyses (including the Mallmann plots,the relations for the I(I+1) expansion coefficients,energy spectra,etc.)definitely display a systematical deviation of the SU_q(2) prediction from the experimental data available for the even-even rare-earth and actinide nuclei.Only within a limited range of angular momentum the SU_q(2) expression is suitable for rotational spectra.A significant angular momentum dependence of q-deformation parameter is found.The q-deformation is derectly related to the nuclear softness.     

THE VERTICAL INTEGRATED MOMENTUM SPECTRUM OF THE MUON WITH MOMENTUM LARGER THAN 4 GeV/c AT 3220m ABOVE SEA-LEVEL

At an altitude of 3220 meters above sea level in Yunnan Province, we measured, by using a G-M counter-magnetic spectrometer, the vertical integratted momentum spectrum of the cosmic muon with momentum larger than 4 GeV/c. The spectrum obtained from this experiment is expressed by a power function in the form of I（>p）=Q （p+4）^-1.86±0.06(cm^-2·sr^-1·s^-1), where p is in GeV/c and Q is a constant. We also measured the charge ratio of muon in the 4—23 GeV/c momentum range. The result is N_μ/N_μ-=1.26±0.11. The error in the momentum measurement with spectrometer has been discussed and calculated.     

Theoretical Analysis of an Uqp(u2) Model for Ground-State Bands in Even-Even Nuclei

The validity of an U_qp(u₂)model for the nuclear rotational spectrum is systematically analysed by investigating the Mallmann plots and fitting the experimental data for the even-even rare-earth and actinide nuclei.The results show that the theoretical values obtained from the U_qp(u₂) model are in a good accordance with the experimental findings.Thus the U_qp(u₂) model has some advantages over the SU_q(2)model as far as energy levels are concerned. Further more,a relationship between the parameters of deformations and the nuclear softness is also established.     

THE BEHAVIOR OF THE PHASE-SHIFT IN THE BAKAMJIAN-THOMAS THEORY

The behavior of the phase-shift of the Bakamjian-Thomas theory and its relationwith the phenomenological nuclear force V=V_RiV_I at high energy are explored.Two limits are obtained:It is found that the repulsive core with a sharp outer edge may induce a characteris-tic oscillation of Re δ₁,and Im δ₁ is sensitive to V₁.The conclusion is that the analy-sis of the phase-shift extending to higher energy is relevant in determining therepulsive core and the imaginary part of the nuclear force.     

THE MULTIBAND MIXING AND THE i(ω)

The effect for the mixing of the three-band, the g, γ and β bands, on the i(ω) is discussed. The decreasing behavior for i(ω) after some value is interpreted, and it is shown that near the crossing point (ω_c) of the s and g bands, rotation-aligned angular momentum of the quasiparticle is only a part of the total i(ω).     

ON THE IRREDUCIBLE REPRESENTATIONS OF THE COMPACT SIMPLE LIE GROUPS OF RANK 2(I)

In this paper, we analyse the commutation relations of the infintesimal opera-tors of the group SU₃ and find that the eight infinitesimal operators of the groupSU₃ can be written as a scalar operator A, three angular momentum operators (L₁,L_o, L_-1,)and two sets of the irreducible tensor operators of rank 1/2, （T_±1/2,V±1/2）By means of the commutation relations of these operators, all irreducible represen-tations of the group SU₃ can be easily obtained. In this pape, the matrices corresponding to these operators in the irreduciblerepresentation（λμ）, are given; therefore the irreducible representation and its re-presentation space R^λμ are completely defined. Besides, a method for calculatingthe scalar factors of the reduction coefficients and the symmetric relations of thosefactors are also given. As examples, the scalar factors of the reduction coefficientsof （λμ）×（10）, （λμ）×（01）, （λμ）×（20） and （λμ）×（11） are calculated. In the last part of this paper, we define the irreducible tensor operators ofthe group SU₃ and prove the corresponding Wigner-Eckart theory. The method used in the discussion of the group SU₃ be extended to allof the compact simple Lie groups of rank 2 and we shall discuss them in two suc-ceeding papers.     

EXACT SOLUTION OF THE PAULI EQUATION IN THE FIELD OF A 'T HOOFT-POLYAKOV MONOPOLE

In this paper, the motion for the spin one half particles with arbitrary isospin in the field of a't Hooft-Polyakov magnetic monopole (in the Prasad-Sommerfield limit) is studied by the method of the moving frame. An exact solution of the Pauli equation for the total angular momentum J=0 and isospin I=1/2 is presented. The question of Proton decay catalysis is briefly discussed.     

THE STUDY OF SOME NON-SOLATED RESONANCES FOR THE 23Na （p,α）20Ne REACTION

The excitation functions of the ²³Na（p,α₀）²⁰Ne_g·s.and the ²³Na（p,α₁）²⁰Ne_lst reae-tion have been measured from E_p=1 to 2.5 MeV at θ_L=30°,150° and 30°,respectively.Around the resonance at 2.171 MeV,the excitation functions of the（p,α₀）reactionhave been measured at 12 angles,then,some angular distributions have been obtained from these excitation functions.In addition,the angular distribution of the（p,α₀）reaction for the resonance at 2.171 MeV has also been measured directly at energy ofthe resonance peak of the excitation function at 150°.For the resonance at 2.117MeV,the angular distribution have been measured at two energies,one at the energyof the resonance peak of the excitation function at 150°,another at the energy of thehalf maximum point of the resonance peak on the higher energy side.Around the re-sonance at 2.075 MeV,the excitation functions have been measured at 16 angles,andthe angular distribution has been obtained from three excitation functions.The an-gular distributions of the three resonances are not symmetric about 90°,and the posi-tions of the resonance peaks of these resonances varies with the angle of measurement.By means of the compound nucleus theory,discussions have been made for these non-solated resonances.     

MEASUREMENTS OF ANGULAR MOMENTUM EFFECT OF FISSION BARRIER

The fission cross sections and the evaporation residue cross sections for ¹²C+²⁰⁹Bi and ¹⁴N+Pb reactions were measured with the gold surface barrier silicon detectors and the mica nuclear track detectors.The critical angular momentum l_er was deduced from the measured evaporation residue cross section σ_er on the basis of the sharp-off model.The fission barrier with the particular angular momentum i derived from the condition Γ_f/Γ_n=1 at l=l_e The angular momentum effect of the fission barrier was studied experimentally.     

ON THE PHASE AND THE REPRESENTATION TRANSFORMATIONS OF SUn BARYON AND MESON WAVE FUNCTIONS

The baryon and meson wave functions of SU_n symmetry under the Baird-Bie-denharn phase convention are given explicitly.The phase confusion is clarified andthe matrices of transformations between I-spin,U-spin and V-spin representationsare given for the IR（8）,（27）,（35） of SU₃.     

A DISCUSSION OF THE STRENGTH AND THE RANGE OF THE PHENOMENOLOGICAL NUCLEAR FORCE USING EXPERIMENTAL DATA IN HIGH ENERGY SCATTERING

Under the framework of the Bakamjian-Thomas theory,we discuss the qualitativeproperties of the phenomenological nuclear force V=V_R-iV₁ at high energy arediscussed by a comparision with the small angle scattering data.Because these data inhigh energy are insensitive to the spin,we suppose that the nuclear force at highenergies is spin-independent.The followings are obtained:i)for the Gaussian potential,X₃≌200 MeV and β₃≌0.95 fm,which are thestrength and the range of V₁ respectively;ii)in V_R,there is no hard repulsive core.Under a rough estimation,supposingthe range β₁>0.45 fm,we find the strength of the repulsive force,X₁<480 MeV;iii)all parameters are vary very slowly with energy.     

Polarized fluorescence of jet-cooled molecular iodine

The degree of polarized fluorescence of molecular iodine ¹²⁷I₂ cooled in a supersonic jet under rotationally selective excitation in the electronic transition B ³Π_0u ⁺-X ¹Σ _g ⁺ has been measured and calculated. It was found that the interaction of the angular momentum of the molecule with the nuclear spins of iodine atoms leads to a considerable depolarizing effect. This effect is most pronounced for small rotational quantum numbers of the angular momentum that are comparable with the total nuclear spin of the iodine molecule, which is equal to 5.     

MICROSCOPIC CALCULATION OF THE INERTIA IN HEAVY NUCLEI

A realistic calculation of the inertia for ²³⁶U fisson based on the linear response theory is presented, in which the single particle states are provided by Nilsson model. The dependence of the nuclear inertia M_δiδi on the collective variables δ₂, δ₄ is studied at the range of certain nuclear temperature (0—1 MeV). The pairing effect and the shell effect on the nuclear inertia are discussed. The calculated results show a very prominent structure at level crossing points and when acrossing the critical temperature.     

Optical Emission Spectroscopy Investigation of a Surface Dielectric Barrier Discharge Plasma Aerodynamic Actuator

The optical emission spectroscopy of a surface dielectric barrier discharge plasma aerodynamic actuator is investigated with different electrode configurations, applied voltages and driving frequencies. The rotational temperature of N2 （C^3 Ⅱu） molecule is calculated according to its rotational emission band near 380.5 nm. The average electron energy of the discharge is evaluated by emission intensity ratio of first negative system to second positive system of N2. The rotational temperature is sensitive to the inner space of an electrode pair. The average electron energy shows insensitivity to the applied voltage, the driving frequency and the electrode configuration.     

THE OBSERVATION ON o-Ps ANNIHILATION IN SILICA AEROGEL BY COMBINED SPECTROMETER

The yields and energy spectra of the various components of o-P_s annihilation in silica aerogel are observed using the combined spectrometer. It is shown that the processes of P_s formation and annihilation in ultrafine grains of SiO₂ aerogel are basically consistent with the diffusion model, but the grain surface effect can not be neglected. Comparing the Dopplar broadening spectra, it is understood that the pick-off process of the longest component possesses the lower annihilation momentum than that of the free positron annihilation.     

INTERACTING BOSON MODEL FOR ROTATIONAL STATES OF NEGATIVE PARITY

In this paper, rotation of the system consiting of N—1 (sd) bosons and one (pf)boson is discussed on the assumption that the SU(3) limit is just the rotational limit.Using group-theoretical methods, we have given rotational spectra of negative parity,and have derived the analytic expressions of the reduced matrix elements of the E3transition from the v₀-band (K^π=0^-) to the ground band. In terms of the inegualityof the intensities of (sd)-(sd). interaction and (sd)-(pf) interaction, the differencebetween the parmeters of positive-parity bands and those of negative-parity bands areexplained qualitatively.     

ANGULAR MOMENTUM CORRELATION OF FRAGMENTS IN DEEP INELESTIC COLLISIONS

The role of the non-diagonal difusion coefficient D12 of the two dimensional F-P EQ. In the mean value of angular momentum of fragments, their varaince and covaraince are discussed. It is found that D12 doesnot influence the equilibrium value of the quantities, but influences the rate for the quantities to reach equilibrium. So that it mainly influences the angular momentum transfer at the beginning of the reaction and that of large incident angular momentum partial waves. We also find that the covaraince is especially sensitive to D12.     

A Time-Dependent Wavepacket Method for Photodissociation Dynamics of Triatomic Molecule

We report a time-dependent quantum wavepacket theory employed to interpret the photoabsorption spectrum of the N20 molecule in terms of the nuclear motion on the upper 21A＇ and 11A＂ potential energy surfaces. The N2-O bond breaks upon excitation leading to dissociation. The total angular momentum is treated correctly taking into account the vector property of the electric field of the exciting radiation.     

A TWO-NUCLEON MODEL OF THE（p,π-） REACTION

In this paper,we suggest a two-nucleon model of the A（p,π^-） B reaction.Areduced formulation of the reactoin amplitude and a relation between the reactionamplitude and the nuclear structure are given.The differential cross section of ¹³C（p,π^-）¹⁴O_g.s,at E_P=185 MeV is calculated in the plane wave approximation.The results+s can explain the experimental data qualilatively.