Calculation of dipole and quadrupole momentum of CO

In summary, the conversation discusses the use of GAUSSIAN to calculate the dipole and quadrupole moments for the carbon monoxide molecule using different levels of theory. The poster is having trouble with the calculation of the quadrupole moment, which shows a deviation of about 50% from the values found in a reference paper. They suspect that the input file may be incorrect, but the dipole moment calculation matches both experimental and computational results. The references used are from a paper by Siegfried Hofinger and Martin Wendland. The experimental and calculated values for the quadrupole moment are also mentioned. The poster also shares their input and output files and asks for help in resolving the issue.
  • #1
deFe_9807
2
1
This is my first post of this topic so I hope it is in the correct place.
I need some help to figure out the using of GAUSSIAN in order of calculate the dipole and quadrupole moment for the carbon monoxide molecule with different levels of theory (SCF and Post Hartree Fock methods). In particular, I have some problem in quadrupole momentum calculation.

I'm considering the traceless quadrupole moment tensor for my calculation and because CO is a linear molecule it is sufficient to use only the zz component. The value I carry out from the calculation are significantly different from the experimental (and so the value found by some authors who carried out the same calculation) but they show a deviation of circa 50% from the values in the paper I'm using as reference.

I thought that probably I wrote the input file wrong, but the dipole moment matches both the experimental and the computational results.

TheGAUSSIAN input file I wrote contains the keywords Density=current and Prop=Dipole.

I hope someone could help me.

Thank you!
 
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  • #2
Sorry, the information in this post isn't very clear and I can't follow. Can you list for us the references you mentioned, and list the values you calculated as well as the literature results (both theory and experiment)? Can you also share your input file (if it's in an ASCII or other freely readable format) or summarize the main parameters and their values?
 
  • #3
Hi Twigg,
Yes, sorry for the lack of information. The references I'm using come from the paper "Method/Basis Set Dependence of the Traceless Quadrupole Moment Calculation for N2, CO2, SO2, HCl, CO, NH3, PH3, HF, and H2O" by Siegfried Hofinger and Martin Wendland and these are the result they obtained for the qadrupole moment traceless tensor.
1645617534032.png

In the paper (I don't know if I am allowed to share the pdf here) they say that, in order to compute the quadrupole moment traceless tensor, they used another software developed by themselves.
In the next Table I list the results that I carried out with the GAUSSIAN
1645618021329.png

I share to you also one of the input files I wrote (the other are the same but I just changed the method and the basis set) and the correspondig output file.
The experimental value is obtained from https://cccbdb.nist.gov/quadlistx.asp#1998Gra/Imr:49 and for CO it is -9.47± 0.15 ⋅10-40 C⋅m2 (-2.1107± 0.034 a.u.). The calculated value used as reference is -1.44±0.03 a.u. (Wolinski, K.; Sadlej, A. J.; Karlström, G. Mol Phys 1991, 72, 425–432).

Thank you for your availability and I hope this post is clearer than the previous.
 

Attachments

  • input_CO_multipole.txt
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  • out_CO_B3LYP_6-31G+polarized_multipole.txt
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Related to Calculation of dipole and quadrupole momentum of CO

1. What is the dipole moment of CO?

The dipole moment of CO is 0.112 Debye, which is a unit of electric dipole moment measurement. It indicates the separation of positive and negative charges in a molecule.

2. How is the dipole moment of CO calculated?

The dipole moment of CO is calculated by multiplying the magnitude of the charges (in Coulombs) by the distance between them (in meters). This calculation takes into account the geometry of the molecule and the distribution of charges within it.

3. What is the quadrupole moment of CO?

The quadrupole moment of CO is a measure of the distribution of electric charge within the molecule. It is a higher-order moment than the dipole moment and provides information about the shape and symmetry of the molecule.

4. How is the quadrupole moment of CO determined?

The quadrupole moment of CO is determined by calculating the moments of inertia of the molecule, which take into account the masses and positions of the atoms within it. This information is then used to calculate the quadrupole moment using mathematical formulas.

5. What factors affect the dipole and quadrupole moments of CO?

The dipole and quadrupole moments of CO are affected by the electronegativity of the atoms involved, the geometry of the molecule, and the distribution of charges within it. They can also be influenced by external electric fields and molecular vibrations.

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