Quadrapole and octupole

Sunghwan Choi · 2020-06-18 14:41:51

Hi, I'm a newbie.
In order to calculate electric quadrupole and octupole from the density matrix, I need quadrupole and octupole momentum matrices
For dipole moment, Manual (section 3.200.2) tells details but I cannot find how to build quadrupole and octupole momentum matrices.
Is it possible to build those matrices through Multiwfn?

sobereva · 2020-06-18 15:37:59

Multiwfn doesn't have a function to export electric quadrupole and octupole momentum integral matrices. If you want to calculate molecular electric quadrupole and octupole based on a given wavefunction file, I can add a new function to Multiwfn to realize this.

Sunghwan Choi · 2020-06-19 02:05:04

Yes!! I need it!! I really appreciate for adding those features~ Can you estimate the development period for those features?

sobereva · 2020-06-19 07:19:11

I have updated Multiwfn 3.7(dev) on Multiwfn website. Now using subfunction 2 of main function 15, molecular dipole/quadruple/octopole moments will be outputted at the end. For example, using examples\uracil.wfn as input file, the outputted information is (all units are a.u.)

***** Molecular dipole and multipole moments ***** Total number of electrons: 58.000039 Molecular dipole moment (a.u.): 0.473288 1.823815 0.000736 Molecular dipole moment (Debye): 1.202978 4.635675 0.001871 Magnitude of molecular dipole moment (a.u.&Debye): 1.884225 4.789221 Molecular quadrupole moments (Standard Cartesian form): XX= -43.878912 XY= 1.812527 XZ= -0.000544 YX= 1.812527 YY= -28.230912 YZ= -0.004829 ZX= -0.000544 ZY= -0.004829 ZZ= -34.463390 Molecular quadrupole moments (Traceless Cartesian form): XX= -12.531761 XY= 2.718791 XZ= -0.000816 YX= 2.718791 YY= 10.940239 YZ= -0.007244 ZX= -0.000816 ZY= -0.007244 ZZ= 1.591522 Magnitude of the traceless quadrupole moment tensor: 13.644701 Molecular quadrupole moments (Spherical harmonic form): Q_2,0 = 1.591522 Q_2,-1= -0.008364 Q_2,1= -0.000942 Q_2,-2= 3.139390 Q_2,2 = -13.551565 Magnitude: |Q_2|= 14.001204 Molecular octopole moments (Cartesian form): XXX= 14.09463 YYY= 8.61373 ZZZ= 0.00275 XYY= 6.66406 XXY= 46.41021 XXZ= -0.00991 XZZ= 2.78071 YZZ= -7.68402 YYZ= 0.01589 XYZ= -0.00333 Molecular octopole moments (Spherical harmonic form): Q_3,0 = -0.006233 Q_3,-1= -52.517080 Q_3,1 = -5.900743 Q_3,-2= -0.012895 Q_3,2 = -0.049957 Q_3,-3= 103.261734 Q_3,3 = -4.662433 Magnitude: |Q_3|= 116.093019

You can use any input file containing GTF information for this function, for example, wfn/wfx/mwfn/fch/molden/gms. Note that the data is not calculated based on density matrix, but calculated based on the orbitals in the input file.

Sunghwan Choi · 2020-06-20 02:54:49

I really appreciate your effort!
I have two questions. 1) is it possible to get quadrupole octupole moment matrices through Multiwfn? I have density matrices in an unusual format. so I want to read the density and operator matrix and calculate matrix multiplication with operator and get a trace of it.
2) I downloaded and check the 3.7(dev) source file but I couldn't find quadrupole/octupole moment integral functions in integral.f90 which I expect to contain the functions. Did you only upload binary files? (I didn't check binary yet)

sobereva · 2020-06-20 05:17:52

1 Currently it is not possible. But I will try to find time recently to implement this feature, then I will let you know here. (It is expected I can finish within one week)

2 This part of code is realized in fuzzy.f90.

Sunghwan Choi · 2020-06-21 23:20:29

Thank you so much. I will be waiting for your notice~

sobereva · 2020-06-26 21:16:33

I am glad to inform you that the function you need has been finished.
I just updated Multiwfn 3.7(dev) on Multiwfn website, in subfunction 7 of main function 6, now you can select to export electric quadrupole and octopole moment integral matrices to a text file.
In addition, subfunction 5 is newly added in main function 300, it is able to calculate electric dipole, quadrupole, octopole moments very quickly and analytically based on current density matrix and integral matrices.

Sunghwan Choi · 2020-06-29 23:08:43

Thanks~ I checked what you did!
It works fine!

Multiwfn forum

#12020-06-18 14:41:51

Quadrapole and octupole

#22020-06-18 15:37:59

Re: Quadrapole and octupole

#32020-06-19 02:05:04

Re: Quadrapole and octupole

#42020-06-19 07:19:11

Re: Quadrapole and octupole

#52020-06-20 02:54:49

Re: Quadrapole and octupole

#62020-06-20 05:17:52

Re: Quadrapole and octupole

#72020-06-21 23:20:29

Re: Quadrapole and octupole

#82020-06-26 21:16:33

Re: Quadrapole and octupole

#92020-06-29 23:08:43

Re: Quadrapole and octupole

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