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I have 106 atoms in my system and the basis set used is B3LYP/6-311G(D)

Please we need information on how to specify 6-31G basis set for organic system with C, H, N, O and LANL2DZ for Copper(ii) complex in the input file in order to compute molecular properties of the system.

Hello fellow researchers,

How to tackle the bonding properties of complexes with lanthanide metals?

What are the best density functionals and basis sets can be used to describe the energetics and bonding properties in these complexes?

Are casscf/caspt2 calculations helpful?

Any lead in this topic will be helpful?

Thank in advance.

Ranajit

This question might sound a little bit silly, but it's my first time using DFT on my calculations. I've always used HF to do SAR of active molecules on diverse targets, but now that I started using density functional I wonder: is it more accurate than HF calculations using the same basis set?

Just to exemplify one of my typical calculations: 

a) conformer distribution

b) equilibrium geometry

c) calculation of properties (homo and lumo distribution, eletrostatic potential map etc) using HF method.

Greetings,

As part of my research, I am interested in studying the magnetic properties of coordination polymers using the ORCA chemistry program package.

The main goal is to calculate the isotropic exchange constant J using the broken symmetry approach.

My question is related to the input file. What should I add exactly in order to obtain such parameters?

P.S: The calculation can be carried out with the hybrid B3LYP functional using Aldrich’s def2–TZVP basis.

Thanks in advance.

Is it possible theoretical evaluation of fatigue life on the basis of mechanical properties of material?

Please we need information on how to specify two basis sets for biochemical system ( several selected microhelices with three nucleotide base pairs, with pyrimidines in strand I and purines in strand II), 6-311+G(d,p) for C, H, N, O and 6-311 G(d,p) for P (Phosphorus) in the input file in order to compute molecular properties of the system . It should be noted that there are four phosphorus atoms in our structures.

I realize that the GEN keyword in Gaussian allows you to load a custom basis set, what I'm not quite clear on is if I can specify different basis set for four phosphorus atoms or i just can specify this basis sets for the one of them.

thanks in advance

best regards

saber

Materials having no sharp point to indicate the start of the yield (offset method).

I am working with some metal complexes having elements like barium and tungsten. I have optimized them using lanl2dz basis set at hf level and have calculated homo-lumo energy gap. The gap was found to be >7 eV. But from the uv analysis experimentally it was observed that the gap is 4 eV. Why this difference occurs and how to overcome this problem? can anyone help me in this regard?