[en] This work is devoted to nuclear structure studies of superdeformed states in the second potential well. Under focus are the gadolinium isotopes and in particular the ¹⁴⁷Gd nucleus. High spin states in ¹⁴⁷Gd have been populating by ¹²²Sn (³⁰Si,5n)¹⁴⁷Gd fusion-evaporation reaction with a silicon beam of 158 MeV delivered by the VIVITRON accelerator of the Institut de Recherches Subatomiques. The nucleus γ de-excitations have been measured using the EUROGAM II γ-ray multidetector. On the basis of multiple coincidences, four new superdeformed (SD) rotational bands have been assigned to ¹⁴⁷Gd nucleus. Nuclear structures corresponding to these bands have been investigated by shell model calculations using a harmonic oscillator potential with cranking, in the Nilsson Strutinsky formalism. Comparison of dynamical moments of inertia of band (1) and (5) in ¹⁴⁷Gd with ¹⁴⁸Gd(2) and ¹⁴⁶Gd(1) SD bands has fixed the role of the [651 1/2]α = -1/2 orbital crossing frequency. Theoretical calculations reproduce quite well the ¹⁴⁸Gd(2), ¹²⁷Gd(1,5) and G¹⁴⁶Gd(1) dynamical moments of inertia. Using the particle hole excitation nature of ^{149,148,147,146}Gd bands, effective spin alignment of [651 1/2]α= ±1/2, [770 1/2]α = -1/2 and [441 1/2]α = +1/2 orbitals have been deduced from the experiment in agreement with the theoretical values. Of particular interest, the spin alignment measured for the [441 1/2]α +1/2 orbital, with a value close to zero, is in contradiction with the value predicted by the Pseudo SU(3) model, formalism often used to explain the identical band phenomenon. (author)