TEMPERATURE DEPENDENCE OF THE PURE NUCLEAR QUADRUPOLE RESONANCE FREQUENCY IN KClO3

1960 ◽  
Vol 38 (11) ◽  
pp. 1397-1405 ◽  
Author(s):  
J. Vanier

The resonant frequency of the Cl35 nuclear quadrupole in KClO3 has been measured as a function of temperature in the range 15 deg;K to 77 deg;K; previous work between 77 deg;K and room temperature has been confirmed. Comparison has been made with Bayer's theory based on lattice vibrations and agreement is excellent. The ratio of the quadrupole coupling constant eQqzz of the two isotopes (Cl35 and CI37) has been measured at room and liquid air temperatures; significant changes have been observed in the measurements. Finally the possibility of using this temperature dependence as the basis of a sensitive thermometer has been studied; the accuracy of such a thermometer would be ±0.005 deg;K at 60 deg;K and ±0.05 deg;K at 20 deg;K.

1972 ◽  
Vol 50 (16) ◽  
pp. 2586-2590 ◽  
Author(s):  
G. C. Gillies ◽  
R. J. C. Brown

The temperature and pressure dependence of the 209Bi nuclear quadrupole coupling constant and asymmetry parameter in solid BiCl3 have been measured near room temperature. It is not possible to account for the results on the basis of the conventional theory in which the field gradient parameters depend only on the crystal volume.


1986 ◽  
Vol 41 (1-2) ◽  
pp. 341-342 ◽  
Author(s):  
S. Sengupta ◽  
S. Rhadakrishna ◽  
R. A. Marino

Aluminum-27 NQR transitions were detected in Muscovite Mica at room temperature using double resonance by level crossing (DRLC) techniques. Three lines were observed with frequencies of 572.5, 1052.0, and 1624.5 kHz. These lines are assigned to the octahedrally coordinated site, AlO4(OH)2. The corresponding quadrupole coupling constant, e2q Q/h, and asymmetry parameter, η, are 3554.8 kHz and 0.265, respectively. The remaining tetrahedrally coordinated sites, AlO4, gave no discernible signal, perhaps due to the greater 27Al- 1H distance.


1968 ◽  
Vol 21 (6) ◽  
pp. 1403 ◽  
Author(s):  
RA Caldwell ◽  
S Hacobian

Nuclear quadrupole coupling constant data are utilized to determine the ionic character of the carbon-iodine bond in a number of substituted iodobenzenes and related to the half-step potential of the corresponding substituted iodobenzene. A semi-empirical discussion using the Kirkwood-Westheimer relation for the interaction of poles in a continuous medium is given as the basis for such a relationship.


1989 ◽  
Vol 44 (7) ◽  
pp. 659-668 ◽  
Author(s):  
Armin Kehrer ◽  
Shi-qi Dou ◽  
Alarich Weiss

Abstract The crystal structures of glycyl-l-alanine hydrobromide monohydrate, 1, and glycyl-l-alanine hydroiodide monohydrate, 2, were determined and the temperature dependence of the 127I NQR frequencies was investigated in the temperature range 77 <̳T/K <̳ 370. The 127I NQR frequencies are strongly influenced by hydrogen bonds and this is proved by the frequency shift of the H ⇄ D exchange. By deuteration the nuclear quadrupole coupling constant e2 qQh−1(127I) of 2 is shifted downwards 2.72 MHz at room temperature. The title compounds are isotype, and at room temperature they crystallize monoclinic with the space group C22 − P21 with two molecules in the unit cell. The lattice constants for 1 are a = 1068.7 pm, b = 614.1 pm, c = 762.0 pm, and β= 108.55° and for 2 are a = 1093.3 pm, 6 = 637.1 pm, c = 770.9 pm, and β= 107.29°.


1996 ◽  
Vol 51 (5-6) ◽  
pp. 769-772 ◽  
Author(s):  
Hae Jin Kim ◽  
Kee Tae Han ◽  
Sung Ho Choh

Abstract The temperature dependence of 14N NQR, measured at 77 to 300 K, is in better agreement with the model proposed by Blinc et al. than the Bayer theory. The nuclear quadrupole coupling constant and asymmetry parameter show a discontinuity at about 160 K and 230 K, respectively. The linewidths are broadened at these temperatures up to 22 kHz and 18 kHz, respectively. These results indicate that KNO2 undergoes phase transitions at these two temperatures.


1970 ◽  
Vol 25 (7) ◽  
pp. 1155-1156
Author(s):  
Tae-Kyu Ha ◽  
Chester T. O’Konski

The nuclear quadrupole resonance (NQR) spectra of 14N in ethylenimine have been detected at 77 °K. Comparing to the reported microwave experiment on the gaseous state, it is found that the solid state shift in the quadrupole coupling constant is much smaller than that of ammonia


2009 ◽  
Vol 08 (04) ◽  
pp. 647-656 ◽  
Author(s):  
NASSER ZAMAND ◽  
ALI R. ALIAKBAR ◽  
NASSER L. HADIPOUR

Nuclear quadrupole coupling constant, χ, and asymmetry parameter, η, of 14 N nucleus and 13 C , 1 H , and 15 N chemical shifts for cyclotrisazobenzene at the level of B3LYP and MP2 methods have been studied using the Gaussian 98 suite of programs. Also, nuclear quadrupole resonance (NQR) frequencies (ν0, ν+, ν-) for 14 N have been calculated, thoroughly. The optimized structure of the compound was very similar to that given by the X-ray crystallographic data. The electric field gradient (EFG) calculation verified that the N = N bonds are highly localized in this molecule; therefore, electron-pairs of the nitrogen atoms remain nonbonding. The comparison of the calculated chemical shifts with the experimental values for cyclotrisazobenzene shows no significant structural changes in solution.


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