Experimental aspects of ^(14)N overtone RESPDOR solid-state NMR spectroscopy under MAS beyond 60 kHz

Nitrogen-14(^(14)N)overtone(OT)spectroscopy under fast magic angle spinning(MAS)conditions(>60 kHz)has emerged as a powerful technique for observing correlations and distances between ^(14)N and ^(1)H,owing to the absence of the first-order quadrupolar broadenings.In addition,^(14)N^(OT) allows selective manipulation of ^(14)N nuclei for each site.Despite extensive theoretical and experimental studies,the spin dynamics of ^(14)N^(OT) remains under debate.In this study,we conducted experimental investigations to assess the spin dynamics of ^(14)N^(OT) using the rotational-echo saturation-pulse double-resonance(RESPDOR)sequence,which monitors population transfer induced by a^(14)N^(OT) pulse.The ^(14)N^(OT) spin dynamics is well represented by a model of a two-energy-level system.Unlike spin-1/2,the maximum excitation efficiency of ^(14)N^(OT) coherences of powdered solids,denoted by p,depends on the radiofrequency field(rf-field)strength due to orientation dependence of effective nutation fields even when pulse lengths are optimized.It is also found that the p factor,contributing to the ^(14)N^(OT) spin dynamics,is nearly independent of the B0 field.Consequently,the filtering efficiency of RESPDOR experiments exhibits negligible dependence on B0 when the ^(14)N^(OT) pulse length is optimized.The study also identifies the optimal experimental conditions for ^(14)N^(OT)/^(1)H RESPDOR correlation experiments.

Statistics of Seismic Tremors with Harmonic Overtones Recorded at Syowa Station, Antarctica: October 2014-March 2015

During the period from October 2014 to March 2015, a total number of 82 seismic tremors and 66 ice-quakes were identified in both three-component short-period seismographs (HES) and broadband seismographs (STS-1) at Syowa Station (SYO), Antarctica. Statistics of the number of these tremors indicated that many tremors were likely to occur when large increases in temperature and/or wind speed during the period. This implied that the rapid increase in temperature enhanced a melting speed of cryosphere environment with generating seismic energy;the tremors were also excited by stormy conditions, associated with interactive resonance between sea-ices and oceanic swells. The characteristic tremors of harmonic overtones with strong amplitudes were explained by repetitive sources, suggesting inter-glacial asperities such as the collision of icebergs and fast sea-ice, calving of glaciers/ice-streams at the coastal environment of Antarctica. These high amplitude tremors occurred independently from other majority types of events, characterized by non-linear, small amplitude and weak signals at the stormy condition and rapid increase in temperature.

OH…O Out-of-Plane Bending Band [γ(OH)] and Its Overtone Band of Dimethylol Propionic Acid(DMPA)

In the present paper are reported the OH…O out-of-plane bending band[γ(OH)] between 900—950 cm -1 of dimethylol propionic acid(DMPA), its dependence upon temperature and its overtone band investigated via FTIR spectroscopy. It has been found based on the crystal structure that the band [γ(OH)] may not certainly be the characteristic band of carboxylic dimers, it can also result from another H-bond formed between carboxylic carbonyl and the primary hydroxyl. In addition, the band [γ(OH)] is very sensitive to temperature change but its overtone band can only appear at a low temperature.

Two Great Transfers of Word Emotive Overtones In Modern Chinese

Since 1949, modern Chinese language has, in the course o f its development in China's Mainland, twice witnessed large-scale transfers in its word emotive overtones. The first began in 1949 and went on all the way till the end o f the Cultural Revolution in 1977. Derogation manifested itself in that period, during which the derogatory words enjoyed their greatest number, widest usages and highest frequency in the history o f the Chinese language. The second began from the Reform and Opening Up Policy in 1978 and lasted untill now. De-derogation has manifested itself in this period, during which the derogatory words have had the smallest number, least usages and lowest frequency in the history o f the Chinese language. The two large-scale transfers result from their specific social backgrounds and the development o f the Chinese language itself.

ISOTOPIC SUBSTITUTION RULES OF X-H STRETCHING VIBRATIONAL OVERTONE

Ⅰ. INTRODUCTIONIsotopic frequency shifts of vibrational frequencies of polyatomic molecules bring much benefit to the determination of force field constants. There are a variety of isotopic substitution rules for molecular vibrational fundamental frequencies, all of which are based on the GF matrix method, that is, with small vibrational amplitude approximation. For X-H(X=C, N, O, S, etc.) stretching vibrations with large anharmonicity, we discover at least

RELATIONSHIPS BETWEEN X—H STRETCHING OVERTONE FREQUENCIES AND BOND LENGTHS/BOND ANGLES

A relationship between the X-H (X = N, O, C, and so on) equilibrium bond length in a Morse oscillator and the X-H stretching overtone frequency shifts is obtained theoretically. We use the equation to discuss the empirical linear relationships that have been proposed for heterocyclics, alkanes and fluorinated benzenes. On the other hand, a unified relationship between the X-H bond angles and the experimental quantities (ω(?) and the coupling strength λ) is also presented for XH2, XH, and XH4 molecules or molecular fragments. Calculations of X-H bond angles for a number of molecules show that the results from our equations are in excellent agreement with the experimental values. Also we can extract the information of relative magnitude of bond coupling force field.

Overtone神奇的乐响(一)——小提琴自然泛音(下)

经典范例小提琴传世经典作品中,常有自然泛音的运用,如:拉威尔《茨岗》:维尼亚夫斯基《谐谑塔兰泰拉》:

Anharmonic oscillator model of overtone spectra for D_(3h) symmetry molecules

The bond stretching vibrations of XF_5 molecules with D_(3h)symmetry are treated computa- tionally on the Morse oscillator model in which the bond oscillators are coupled harmonically.Each calculation involves four parameters for two types of Morse potential and three parameters for the kinetic-energy,potontial coupling terms.The eigenvalue formula for overtone and combination states up to three are presented and can be used to predict all the vibrational energylevels from local mode molecules through normal mode molecules.For PF_5,AsF_5 and VF_5,the coupled Morse oscillator model gives a prediction in good agreement with the experimental data.

Overton算法收敛性的一个结论

Overton 在[1]中对一般最优场址模型给出了一个具二次终端敛速的算法.但未能证明该算法的收敛性.本文在一定条件下证明了 Overton 算法具有全局收敛性.

Three-dimensional ab initio dipole moment surfaces and stretching vibrational band intensities of the XH3 molecules

Stretching vibrational band intensities of XH3 （X=N, Sb） molecules are investigated employing three-dimensional dipole moment surfaces combined with the local mode Hamiltonian model. The dipole moment surfaces of NH3 and SbH3 are calculated with the density functional theory and at the correlated MP2 level, respectively. The calculated band intensities are in good agreement with the available experimental data. The contribution to the band intensities from the different terms in the polynomial expansion of the dipole moments of four group V hydrides （NH3, PH3, AsH3 and SbH3） are discussed. It is concluded that the breakdown of the bond dipole approximation must be considered. The intensity “borrowing” effect due to the wave function mixing among the stretching vibrational states is found to be less significant for the molecules that reach the local mode limit.

Surface-enhanced Raman Scattering of Aggregated 2, 2'-Cyanine Adsorbed on Silver Colloid

1 Introduction To our knowledge, cyanine dyes have been widely used as photographic sensitizers and biological fluorescence probes. Recently, the investigation of the optical and nonlinear optical properties of aggregates has attracted considerable attention, because of possible applications of these materials to the field of optical communication and computing. Many studies on the optical dynamics of aggregated cyanine dyes were re-