Vol. 20, No. 2 (1964)
1964, 106 (2): 104-116. doi: 10.7498/aps.20.104
In the present paper, the non-axially-symmetric rotational motion of the odd-A nucleus is treated under the adiabatic condition. The relationship between the non-axial and axial rotation is pointed out. The spectra of Mg25 and Al25 have been analysed in detail. The agreement with experiment is fair. The ground state magnetic moments and reduced E2 transition probabilities between some low-lying states are also calculated.
A dispertion relation for the process ω→π+γ is obtained by the analytical continuation in the ω mass. Some problems concerning dispertion relations involving unstable particles arc discussed. Under simplified assumptions we obtain Wω→π+r/Wω→3π≈0.35 and Wη→π+r/Wη→3π≈25, if η has the same quantum numbers as ω. The effect of the interaction in pairs between three pions is included in the calculation.
1964, 106 (2): 137-146. doi: 10.7498/aps.20.137
The heat conduction problem is transformed into an algebraic eigenvalue problem which can be solved very simply by a perturbation method, the perturbation parameter being the small ratio between the coefficients of heat conduction in the gas and in the solid.
1964, 106 (2): 147-158. doi: 10.7498/aps.20.147
By a new choice of the vacuum state it is shown that the nondegenerate Brueckner-Goldstone linked cluster expansion formula can also be applied to the case where there is one particle outside or one hole inside the closed shell configuration, even though here exists degeneracy.
1964, 106 (2): 164-173. doi: 10.7498/aps.20.164
In the strong electromagnetic field of a laser beam, the third-order process of radiation with two photons absorbed and a third one emitted during a transition between energy levels of a material system may become abservable. This process has analogy with the ordinary Raman effect, in which only two photons are involved. In this paper a theoretical analysis has been given with the conclusion reached, that with a beam intensity of 0.1 MW/cm2 the vibrational Raman spectrum of molecules or crystals may be obtained by the three-photon process. It is shown that this effect actually offers a new spectroscopical method. Its importance lies in the difference of the selection rule of this effect and those of the infra-red absorption and the ordinary Raman effect. It is also pointed out that the stimulated radiation of a three-photon Raman effect may be realized when pumped with a powerful laser beam.