Non-linear susceptibility

Hello everyone, while calculating the nonlinear susceptibility, I found that the non-zero components displayed for the 27 tensor elements (χ, tnlo_6.abo) and the 18 tensor elements (d, tnlo_4.abo) were of the same magnitude. However, in an external paper [PHYSICAL REVIEW B 71, 125107 (2005)] referenced by abinit, it was mentioned that χ=2d. This has left me confused, and I am wondering if I have misunderstood the meaning of the output. Thank you very much!

tnlo_4.abo (17.2 KB)
tnlo_6.abo (247.1 KB)