For the 1D-frustrated ferromagnetic J_1-J_2 model with interchain coupling
added, we analyze the dynamical and static structure factor S(k,omega), the
pitch angle phi of the magnetic structure, the magnetization curve of
edge-shared chain cuprates, and focus on LiCuVO4 for which neither a perturbed
spinon nor a spin wave approach can be applied. phi is found to be most
sensitive to the interplay of frustration and quantum fluctuations. For LiVCuO4
the obtained exchange parameters J are in accord with the results for a
realistic 5-band extended Hubbard model and LSDA + U predictions yielding
alpha=J_2/|J_1| about 0.75 in contrast to 5.5 > alpha > 1.42 suggested in the
literature. The alpha-regime of the empirical phi-values in NaCu2O2 and
linarite are considered, too.Comment: 7 pages, 7 figures, (1 figure added), improved text including also
the abstract (the present second version has been submitted to EPL
26.10.2011, so far with one missing first referee report