Static properties of theS=1 one-dimensional antiferromagnetAgVP2S6

NMR frequency shift has been measured at ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$ and ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$ sites in a single crystal of the one-dimensional spin-1 antiferromagnet ${\mathrm{AgVP}}_2$ ${\mathrm{S}}_6$. Parameters in the single-ion spin Hamiltonian were determined from the orbital (van Vleck) shift at V sites. Temperature dependence of the spin shift (spin susceptibility) is consistent with the theoretical prediction and the magnitude of the Haldane gap determined from neutron-scattering experiments.