Mr. Saha,

You can obtain g-factor in a tabulated form like the example shown below (data about H2O and isolated Cu2+ ion). There are presented the g-tensor components along with shifting of g-values towards g of the free electron; SO contribution and more.

The shown output is obtained "directly" (You need frequency test VCD; Details are given in Gaussian's manual www.).

You can obtain spin-orbital energies, in order to compute g-factor, via CASSCF approach as well as, but is not directly.

Data for the H2O:

::::::::::::::::::::::::::::::

Inverted reduced A of dimension 40 with in-core refinement.

Calculating GIAO nuclear magnetic shielding tensors.

SCF GIAO Magnetic shielding tensor (ppm):

1 O Isotropic = -757.4352 Anisotropy = 1405.9404

XX= -1968.9789 YX= -0.0135 ZX= 0.0000

XY= -0.0109 YY= -483.1851 ZY= 0.0000

......................................................................................

Eigenvalues: -23.2148 25.3124 29.5835

g value of the free electron [g_e]: 0.20023193D+01

relativistic mass correction [g_RMC]:-0.84741557D-03

diamagnetic correction to g tensor [g_DC]:

XX= 0.49530247D-03 YX= 0.54008828D-08 ZX= 0.00000000D+00

XY=-0.19344427D-10 YY= 0.32566817D-03 ZY= 0.00000000D+00

XZ= 0.00000000D+00 YZ= 0.00000000D+00 ZZ= 0.37157827D-03

orbital Zeeman and spin-orbit coupling contribution to g tensor [g_OZ/SOC]:

XX= 0.24737148D-01 YX= 0.38828576D-07 ZX=-0.56149014D-39

XY= 0.49122595D-07 YY= 0.90297338D-02 ZY= 0.14430685D-37

XZ= 0.45243961D-39 YZ= 0.35835978D-41 ZZ=-0.17899344D-02

g tensor [g = g_e + g_RMC + g_DC + g_OZ/SOC]:

XX= 0.20267043D+01 YX= 0.44229459D-07 ZX=-0.56149014D-39

XY= 0.49103250D-07 YY= 0.20108273D+01 ZY= 0.14430685D-37

XZ= 0.45243961D-39 YZ= 0.35835978D-41 ZZ= 0.20000535D+01

g shifts relative to the free electron (ppm):

xx= -2265.8 yy= 8508.0 zz= 24385.0

.............................

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Data for the Cu2+:

:::::::::::::::::::::::::::::::::::::::

g value of the free electron [g_e]: 0.20023193D+01

relativistic mass correction [g_RMC]:-0.11621830D-02

diamagnetic correction to g tensor [g_DC]:

XX= 0.54542488D-03 YX= 0.00000000D+00 ZX= 0.00000000D+00

XY= 0.00000000D+00 YY= 0.54542487D-03 ZY= 0.00000000D+00

XZ= 0.00000000D+00 YZ= 0.00000000D+00 ZZ= 0.34793886D-03

orbital Zeeman and spin-orbit coupling contribution to g tensor [g_OZ/SOC]:

XX= 0.50012839D+00 YX=-0.89524771D-39 ZX= 0.59306305D-39

XY= 0.46774004D-39 YY= 0.50012839D+00 ZY= 0.47117853D-40

XZ= 0.21150148D-44 YZ=-0.35492272D-44 ZZ= 0.73440540D-12

g tensor [g = g_e + g_RMC + g_DC + g_OZ/SOC]:

XX= 0.25018309D+01 YX=-0.89524771D-39 ZX= 0.59306305D-39

XY= 0.46774004D-39 YY= 0.25018309D+01 ZY= 0.47117853D-40

XZ= 0.21150148D-44 YZ=-0.35492272D-44 ZZ= 0.20015051D+01

g shifts relative to the free electron (ppm):

xx= -814.2 yy= 499511.6 zz= 499511.6

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Thank you for answering, it will help me a lot.

But how we are interpret the g values from the output file? Suppose the Cu(II) ion generally shows a average g value approximately of 2.10, but from the above data how I found the g value of the Cu(II) complex??? How I get the rhombic three g values from the calculated data?

Mr. Saha,

Please pay attention to the attachment. It provides you the answer to your question.

Thank You very much Madam

I prefer ORCA as one can do the calculations at the relativistic DKH2 method.

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