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

#1 2020-06-18 14:41:51

Quadrapole and octupole

#2 2020-06-18 15:37:59

Re: Quadrapole and octupole

#3 2020-06-19 02:05:04

Re: Quadrapole and octupole

#4 2020-06-19 07:19:11

Re: Quadrapole and octupole

#5 2020-06-20 02:54:49

Re: Quadrapole and octupole

#6 2020-06-20 05:17:52

Re: Quadrapole and octupole

#7 2020-06-21 23:20:29

Re: Quadrapole and octupole

#8 2020-06-26 21:16:33

Re: Quadrapole and octupole

#9 2020-06-29 23:08:43

Re: Quadrapole and octupole

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