This paper reports the measurement of five new sets of mid-infrared (MIR) laser magnetic resonance spectra (LMR) of the v₃ band (001-000) of ¹⁴N¹⁶O₂ in its ground electronic state. It details the research background, experimental apparatus, and some results obtained. With the intracavity saturated absorption technique employed and the conditions of the phase sensitive modulation detection optimized, spectra of very high sensitivity and resolution have been obtained. These spectra are eligible for studying the structure and Zeeman property of ¹⁴N¹⁶O₂.

In the presence of strong radiation damping, the conventional two-pulse inversion recovery measurements have been performed on water sample(90%H₂O/10%D₂O). It shows that if two pulses in IR sequence are 180° out of phase and the flip angle of the inversion pule is smaller than 180°, or if two pulses are in phase and the flip angle of the inversion pulse is larger than 180°, the signal intensity will continuously changes with the recovery time. Conversely, if two pulses are in phase (or 180° out of phase) and the flip angle of the inversion pulse is smaller than 180° (or larger than 180°), the signal intensity will jump from the negative maximum to the positive maximum around τ=T_rdln{tan[(π±δ)/2]}. Under the off-resonance condition, no matter what pulse phase, the beating effect can be always observed, but the phase of the signal explicitly depends on the relative phase of the pulses. As a result, the phase cycling will greatly suppress the beating effect. These phenomena can be well explained by the radiation damping theory. In addition, when the magnetization locates near the-zaxis during the detection, the deviation of theoretical expectation from the experimental data is closely related to the longitudinal relaxation effect.

Electron paramagnetic resonance (EPR) measurement of single crystal CuGeO₃ has been performed at 96GHz in 14K with 3.5T for a main axis g-factor. The admixture of d-orbital in the ground state wave function of Cu²⁺ ion in the spin-Peierls system CuGeO₃ is derived. The g-factor is calculated with the aid of the approximate self-consistent field d orbit of Cu²⁺ ion. The experimental results can be well interpreted by the present theory.

The VAS (Variable Angle Spinning) NMR method was applied in the study on the Boron containing ZSM-12 and ZSM-5 zeolites. By the ¹¹B VAS NMR experiment and simulations of the powder patterns, the quadrupolar constant of the tri-coordinated boron was determined to be 2.4MHz, and the electrical field gradient coefficient 0.0. The resonance of the Boron-Silicon hydroxyl proton is at 2.3ppm, and by the ¹H{¹¹B} spin echo double resonance it is shown that the 2.3ppm protons are very weakly coupled with the boron atoms. Besides the 6.5ppm adsorbed water peak, a 2.7ppm water adsorption peak was also found, whose position is the same with the extra framework Al hydroxyls. This kind of water adsorption signal can be distinguished by the ¹H{²⁷Al} spin echo double resonance experiment.

¹³C NMR chemical shifts of a new drug for antitutor-β-elemene have been studied by quantum chemical calculation. The calculations both at the ab initio Hartree-Fock and B3LYP density function level of theory (6-31G^*) at the molecular mechanics MMX and Quantum chemistry RHF/6-31G^*(or B3LYP/6-31G^*) optimized geometry have been implemented. Comparisons of both error analysis and linear correlation analysis have been performed between the theoretical and experimental chemical shifts. The results using GIAO gauge transformation method are better than those using CSGT method. The results using GIAO-B3LYP/6-31G^*//B3LYP/6-31G^* level are the best, with RMS of 4.3ppm, correlation coefficient R₂ of 0.998, SD of 2.42ppm. GIAO B3LYP/6-31G^*//MMX is a good method of counterpoising between the computational expense and accuracy of results, with RMS of 4.9ppm, R₂ of 0.996, SD of 3.04ppm.

In the excited triplet molecule/TEMPO/EG system, we obtained E+E/A polarized pattern. Based on the interaction model of excited triplet molecule and doublet radical, considering the hyperfine interaction of free radical and using the second order perturbation theory and density matrix of interaction representation, we calculated the radical spin polarization of the systems.

A new pulse sequence for noise reduction in phase sensitive HMQC experiment is proposed by setting 90°_x(¹H)-τ/2-180°_x(¹H,¹³C)-τ/2-90°_x(¹H,¹³C) and 90°_x(¹³C)-τ/2-180°_x(¹H,¹³C)-τ/2-with τ=(2J_CH)^-1 (J_CH is the one-bond coupling constant) as the preparation and the mixing schemes, respectively. The suppression of signals of protons attached to carbon-12 can be achieved in only one scan irrespective of pulse phase cycles. The proposed method provides an alternative approach for noise reduction in HMQC measurements.

The structural characteristics of N-phosphorylated branched peptides 2-5 in solution have been studied by NMR. Diastereotopic phenomena, the interaction of hydrogen bonds and no regular secondary structures have been observed. It has been shown that participation of phosphoryl group only affects amino acid, which was bond on the phosphoryl group. Due to the formation of peptide planes and the increase of the effect of hydrogen bond between inter or intra-molecules, the position of P=O group relating with C_β=O group in compounds 2 5 was changed from trans into gauche conformation as compared with that in Dipp-Ala of compound 1. The phosphoryl group was still lain on trans position with N-C_α group. It suggests that there is not any polar groups on the side chain of the amino acid. These structural characteristics will provide some evidence for their studies.

The tautomerism of hymexazol was confirmed by GC-MS and ¹H NMR analysis. ¹H NMR of hymexazol under different temperatures indicated that the isomerization of hymexazol was affected slightly by temperature changes. And the main isomer was enol which was about 98.2% at 20℃. The result also proved that GC analysis was reliable for the sample.

The ¹³C NMR data of 5 new 4-cycloalkylbenzonitriles are reported and their structures were determined. The ¹³C chemical shifts of all the 5 compounds have been assigned. The factors of influencing the chemical shifts are discussed.

The quantitative relationship between the EPR zero-field splitting parameter D and the structure parameters of the tetragonal Cr³⁺ centre in KCdF₃:Cr³⁺ crystals has been established according to the superposition model and third-order perturbation theory. The existence of Cd²⁺ vacancy and the lattice distortion have been verified. Meanwhile, we observed that the F^- ion moves toward the central Cr³⁺ ion by Δ₁=0.00294nm, Δ₂==0.0010nm, Δ₃==0.0028nm (see Fig.2). Good agreement between the theoretical values and the experimental results shows that the assumption of the Cd²⁺ vacancy and the lattice distortion is reasonable. Although the main source of the tetragonal crystal field comes from the Cd²⁺ vacancy caused by the charge compensation, the contribution of the lattice distortion can not be neglected.

The digitalization for RF system of NMR spectrometer is the improvement of modern NMR spectrometer, and the replacement for analog quadrature phase-detection with digital phase-detection is a new technology for digital receiver. After analyzing the principle and difficulties of analog QPD receiver, the article introduces the principle of digital QFD, oversampling and IF-sampling, and the implement of digital receiver on MSL-400 spectrometer.

The application of digital signal processing technique in Nuclear Magnetic Resonance digital acquisition and process system, which has been used in our laboratory, is introduced, and its principles and characters are also discussed.