Unfortunately, it seems that this is not possbile. Gaussian is not able to generate transition density between the ground state and excited state calculated by CASSCF (the density=transition=x keyword is only available for CIS-like methods). I am not sure about the case of ORCA, but is seems that ORCA can't do this either.

Best regards,

Tian

]]>For electron analysis methods that based on configuration state coefficients, such as hole-electron analysis, transition density matrix analysis and so on, currently only ZINDO, CIS, TDHF and TDDFT are supported, the methods involving more than singly excited configurations are not supported.

For other analysis methods, such as density different analysis, the function can be used if natural orbitals of corresponding excited state are available. Therefore, these methods can be used if ORCA is able to generate DLPNO-STEOM-CCSD natural orbitals and store it in .gbw or .molden file, but I am not sure if ORCA can do this, please consult the manual and have a try.

Best,

Tian

]]>If the files are large, you can send them to my E-mail (see first page of Multiwfn manual)]]>

There are two known popular ways to calculate charge transfer based on orbital interaction, the first one is the NBO, the charge transfer is evaluated based on off-diagonal terms of Fock matrix (which reflects coupling strength between NBO pairs) and diagonal terms of Fock matrix (corresponding to NBO energies); the second way is charge decomposition analysis (CDA), which is supported by Multiwfn, see Section 4.16 of Multiwfn manual for example. CDA is employed very commonly for studying charge transfer between transition metal and ligands. The difference in these two ways is that the former is analyzed based on NBO orbitals, while the latter is usually based on molecular orbitals calculated for respective fragments.

Evaluation of charge transfer (delta_q) in terms of these orbital interaction models is able to get deeper insight into the nature and source of charge transfer phenomenon, however, the net amount of delta_q obtained in these ways are never as accurate as the delta_q calculated by summing up atomic charges as fragment charge (and then compare it with the net charge of the fragment at isolated state), because orbital interaction models ignore possible high-order interactions, polarization and coupling between different interacting orbital pairs.

So, both kinds of ways of evaluating delta_q may be used in practical study, they have their own advantages.

Solved Problem, thank you very much Professor.

Sincerely,

Anas Ouled aitouna

(a) If the basis set you used doesn't contain g or h angular moment Gaussian functions, you do not need to care about this problem.

(b) If g or h functions indeed present in your wavefunction (for example, cc-pVQZ is employed for organic system), you may need to write a code to reorganize the indices in the "TYPE ASSIGNMENT" field of the.wfn file. If you open the .wfn file by text editor, you can find "TYPE ASSIGNMENT" field, different indices correspond to different types of Gaussian function. If the definition of the index for g or h Gaussian functions is not in line with Multiwfn, the loaded wavefunction will be wrong and the result will be meaningless.

]]>As explicitly mentioned at the beginning of Chapter 4 of Multiwfn manual, the way of generating .molden file is simply using orca_2mkl XX -molden to convert XX.gbw to Molden input file XX.molden.input, then the XX.molden.input can be directly loaded by Multiwfn.

An additional thing should be noticed is that .molden file doesn't explicitly record nuclear charge, this is a drawback of definition of .molden format. Therefore, when ECP is used, in certain analyses (e.g. electrostatic potential analysis) this problem will result in incorrect result. The solution is given in Section 2.3 of Multiwfn manual, namely you should manually modify the atom indices in this file, because Multiwfn loads atom indices as actual nuclear charges. For example, def2-TZVP is employed for XeH2, the [atoms] section in .molden file is

`[Atoms] AU Xe 1 54 -4.6310166076 0.2883783119 0.0000000000 H 2 1 -0.1145711475 0.2883783119 0.0000000000 H 3 1 -9.1474620677 0.2883783119 0.0000000000`

Because def2-TZVP employs small-core ECP for Xe, namely 28 core electrons are replaced with ECP, in this case Xe only has 26 electrons (in other words, 26 actual nuclear charges), therefore you should manually modify the "54" at the "Xe" line to "26".

In practices, if you do not know how to properly modify the .molden file as stated above, you can consult the output of ORCA. For the XeH2 case you can find

`NO LB ZA FRAG MASS X Y Z 0 Xe 26.0000* 0 131.300 -4.631017 0.288378 0.000000 1 H 1.0000 0 1.008 -0.114571 0.288378 0.000000 2 H 1.0000 0 1.008 -9.147462 0.288378 0.000000`

The value under "ZA" column is the value you should manually replace in the .molden file.

Probably the function introduced in Section 3.200.9 is useful for you, in this function you can manually define a distance threshold used for estimating coordinate number.

]]>Thanks for you help the other time. Please, i want to check for the thermal stability of a 2D structure of about 55 atoms with gaussian09. i saw in one of your response that it can be done by ab inition molecular dynamics in gaussian09. Please, kindly help me on which keyword or method i need to apply in gaussian09.

Since my reply may be useful for other people, I paste my reply here:

I don't exactly know what the 2D structure you are studying. If it is a periodic system, you are unable to use Gaussian to perform AIMD for it, because despite that Gaussian supports periodic boundary condition (PBC) calculation, the speed is extremely slow, it is best to use first principle codes such as CP2K and Quantum Espresso to do the AIMD.

If your system is an isolated cluster, although Gaussian indeed can run AIMD for it, a better choice is using ORCA, because ORCA is freely available, faster, and meantime its AIMD function is easier to use.

It is doesn't matter even if you are not familiar with ORCA, because Multiwfn can easily create proper ORCA input file. Assume that you are using the latest version of Multiwfn, you can do this by inputting below commands in Multiwfn:

examples\CH3CONH2.fch // An example. You can also use .pdb/.xyz/.mol/.wfn...

100 // Other function

2 // Output file or create input file

12 // Create ORCA input file

AIMD.inp // The name of outputted file

0 // Select task

6 // Molecular dynamics

1 // Use B97-3c for the calculation. B97-3c is relatively cheap while reliableNow you can find AIMD.inp in current folder. After properly changing it (the number of cores, memory, temperature and MD steps), you can run it by ORCA. The coordinate will be continuously dumped to pos.xyz in current folder during running. If during simulation, the system doesn't isomerize or dissociate, that means the system is stable under current simulation temperature.

If this calculation is too expensive for you, you can use xtb code developed by Grimme (https://github.com/grimme-lab/xtb/) to run molecular dynamics instead. The xtb is much faster, but the theory employed by xtb (i.e. GFN-xTB) is less reliable and accurate than B97-3c.

Thank you very very much for your help and assistance.

Sincerely,

Anas Ouled aitouna

sobereva wrote:

]]>Yes, you should.