P Magnetic Shielding Constants

This section covers the magnetic shielding constants of the P and H nuclei in phosphane. The variation of the shielding constants with external conditions (phase, temperature, pressure) is treated in the context of chemical shift measurements see Section 1.3.1.4.3.1, p. 182. 

The paramagnetic term aP = -386.56 0.63 ppm was obtained after improving the spin-rotation constants [3] using more accurate rotational constants of PH3 [13, 14]. The ab initio calculated diamagnetic contribution =981.01 ppm was taken from [15]. - The spin-rotation constants for PH3 in the vibrational ground-state [3] were recalculated in line with the PH3 equilibrium geometry. [15] was used as above. - op=-366.43 ppm was derived from the measured spin-rotation constants. The calculation of according [16] yielded 960.83 ppm [3]. 

The analysis of the NMR spectrum of PH3 (at 28 C) in a nematic solvent (A/-(p-ethoxy-benzylidene)-p -/7-butylaniline) led to the shielding anisotropy Ao=-7.5 0.5 ppm [17] which agrees very well with Ao=-7.5 ppm [18], derived with the spin-rotation constants 

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