In this paper a scheme for the laser decelerated alkali metal atomic beam frequency standards is proposed. Atomic beam is decelerated and state selected simultaneously by a resonant laser beam. The velocity of the atoms in beam can be reduced to less than 10m/s. In this process the atoms will automatically get together onto a Zeeman sublevel of the ground state with maximum magnetic quantum number by the optical pumping effect. To avoid the bending of the beam trajectory by the gravity the atomic beam is deflected by a inhomogeneous magnet and goes vertically upward. Then by the method of serial magnetic resonances the atoms will transfer into m_F=0 clock sublevel. When the atoms pass twice through the single microwave cavity upward and downward by free falling in the gravity, the Ramsey resonance pattern of linewidth about ¹Hz will be produced. The signal is detected by another laser beam. The stability and accuracy of more than one or two order of magnitude comparing with the conventional atomic beam frequency standards are expected. The methods of laser deceleration and state selection, the measure for overcoming the transverse heating, the method of serial magnetic resonances and the apparatus design for obtaining the vertical beam are discussed in detail.

The active intermediates produced in the photolysis of dialkyl phosphites (RO)₂P(0)H (R=C₂H₅, n-C₃H₇, i-C₃H₇, n-C₄H₉) and their mercury derivatives (RO)₂P(0)HgX(X=OAc, Cl, Br)were studied by spin trapping and ESR spectro-scopy. The results showed that radicals (RO)₂ P(0) were formed from the above two types of compounds during UV irradiation, and could be trapped by PBN. From the fact that the homolysis of P-Hg bond is much easier than that of P-H bond, the bonding characteristics of P-Hg bond in the mercury compounds is discussed.

ESR Spectra of molybdenum supported catalysts(Mo-SiO₂) were recorded with various contact time with propene.Two types of Mo⁵⁺-paramegnetic centers were formed during the course of reaction. The one having g_||=1.89,g_⊥=1.94 is due to the distorted octahadral coordination, while the other with g_||=1.86,g_⊥=1.95 is a square pyramidal distorted species.However,they are both approximately of C_4v symmetry. The anisotropic surperfine coupling contants A_||=90.3×10^-4cm^-1,A_⊥=44.8×10^-4cm^-1 of ^95,97Mo⁵⁺-were also detected. Meanwhile, the signals occurerd at ca. g=2.002 and g₁=2.018,g₂=2.011,g₃=2.005 were assigned to coking from propene and anionic radical 0₂^- respectively. LCAO-MO approximate calculations of data led to a set of molecular orbital coefficients. It was found that the plot of △g_||/△g_⊥ vs. △g is linear. Suggestion was made to employas △g_||/△g_⊥=4(△E(B₂→B₁))/(△E(B₂→E)·(β₁/ε)² a better measure of the extent of C_4v distortion for Mo⁵⁺.

1,3-Benzylideneglycerol and 1,2-benzylideneglycerol were obtained by the reaction of glycerine and benzaldehyde. 1,3-Benzylideneglycerol reacted with benzyl chloride and the products of the benzylation were 1,3-benzylideneglycerol benzyl ethers. All of these compounds are the important intermediates of AEPC. Their configurations were assigned based on the ¹H NMR. The existance of con-formational isomers in 1,3-benzylideneglycerol was confirmed. The conversion of configurations and conformations of these compounds in CDCl₃ is also reported here.

A New density operator formalism for describing high-spin nuclei systems-angular momentum product operator and Z operator was proposed. The product operator and {Z} operator evolution formulae were derived under the effect of spin-spin couplings and radio frequency pulses. The theory dercription can be used to analyse NMR multi-pulse experiments for high-spin nuclei systems. Re-focused INEPT, DEPT and Homonuclear Cosy for high-spin nuclei systems were calculated by using the new density operator. The Caculation method is discussed.

A method used for describing the evolution behavior of AX spin system under multipulse sequence is introduced. The method is simple and is easy to understand, at the same time, it makes up the inadequacy of the vector model.

The field-dependent chemical shift caused by hetero-nuclear dipolar interactions is discussed by the averaging Hamiltonian theory, and compared with the results from the second-order perturbation, it was found that the effect of "A" term has been additionally involved. It is shown that the first-order averaging Hamiltonian is generally more precise than the second-order perturbation when the effects of non-secular terms are considered. The field-dependent chemical shifts produced by homo-nuclear dipolar interaction are also discussed.

A new method of Müller's zero-quantum coherence spectrum and an author's application example are introduced.

Today chemical research is hardly conceivable without nuclear magnetic resonance.It has proved to be an exceedingly rich source of information for exploring the structure of molecules in solution, for the investigation of solid materials, and for the study of molecular dynamics. In order to cope with the over whelming information content, an extension to two-dimensional spectroscopy turned out to be indispensible. Two-dimensional spectroscopy has contributed, since its introduction 12 years ago a large number of new powerful techniques for the elucidation of coupling networks by 2D correlation spectroscopy,for the measurement of internuclear distances by 2D cross——relaxation spectroscopy, and for the investigation of chemical exchange networks by 2D exchange spectrosoc-py. These new techniques are particularly elusive for the analysis of large mol-ecules in chemistry and in biology.