Unanswered Questions

39 questions with no upvoted or accepted answers
25
votes
0answers
137 views

In which paper, or at which point in time, did this cross-pollination between the fields of Operations Research and Materials Modeling begin?

Operations Research is a field of mathematics in which optimal or near-optimal solutions are sought for complicated problems. In the modeling of materials, we often optimize Ising models, in which ...
19
votes
0answers
117 views

Benchmarking data for Ewald summation algorithms

Are there good benchmarks available for testing homemade Ewald summation code? Optimally it would be very nice if there was several types of systems. NIST has a very nice benchmark for energies of ...
17
votes
0answers
52 views

Which basis set families were optimized to give the lowest possible variational energy for a given number of orbitals?

Dunning's basis set families (such as cc-pVXZ and aug-cc-pCVXZ) were not optimized to give the lowest variational energy for a given number of orbitals. For example the S-type orbitals are optimized, ...
16
votes
0answers
119 views

Are there problems with the Tran-Blaha modified Becke-Johnson potential (mBJ, a.k.a. TB09) in Quantum ESPRESSO?

I have used the modified Becke-Johnson (mBJ) exchange potential before, as it was developed and implemented in Wien2K by Fabien Tran and Peter Blaha (1). In 2013, Éric Germaneau et al. implemented mBJ ...
15
votes
0answers
57 views

Fermi level change in surfaces with adsorbed molecules

In a DFT standard calculation of a solid 3D material (i.e. bulk metal), one of the properties that can be obtained is the Fermi level $E_F$. This feature is related with the required work to add an ...
14
votes
0answers
57 views

Benchmark transition state geometries in condensed phases

I'm seeking references/benchmarks for transition state geometries of reactions in condensed phases like crystals, zeolites, or surfaces. Basically the system just needs to be considered big, yet ...
14
votes
0answers
73 views

Types of Discrete molecular models

It is often assumed in cheminformatics that molecules with similar physical structure tend to have similar chemical properties [1]. Based on this, our group has used discrete graphs as a model for the ...
14
votes
0answers
78 views
+100

What is band inversion and how to recognize it in band structure?

Band inversion is a key ingredient of a topologically nontrivial material$^1$. What is band inversion? How to recognize it in a band structure? What conclusions can I infer if I observe band inversion ...
14
votes
0answers
84 views

Which bond order theory should I use?

I am studying the interaction of a metal with a nanostructure. As we can not trust graphical software about the bond formation, I decided to analyze them using the software Multiwfn. It happens that ...
14
votes
0answers
66 views
+50

Why do interaction potential parametrizations of bulk systems not work for corresponding nano-systems?

I am studying several thermodynamics properties of crystalline iron oxides ($\ce{Fe3O4}$, $\gamma-\ce{Fe2O3}$) in their solid phases by MD simulations. At the moment, I am facing many difficulties in ...
14
votes
0answers
117 views

What are the alternatives we have to the VEDA 4 vibrational energy distribution analysis software?

Said software is useful when you need to assign the peaks in vibrational spectra to different vibrational modes found in a hessian calculation for a given molecule, as described in Jamróz, Michał H. “...
13
votes
0answers
85 views

How to calculate Special Quasirandom Structure with local ordering?

I have a supercell that has 12 layers, each with four atoms. I want to generate an SQS with local ordering at layer numbers 6, 7 and 8. Rest of the layers should be disordered. I followed the ...
13
votes
0answers
54 views

Help in developing skill in force matching of interatomic potentials?

I am building skills in using force matching from AIMD data (nonlinear least-squares minimization) to generate interatomic potentials for use in classical MD. I understand the concepts of selecting ...
13
votes
0answers
36 views

Tools for Valleytronic Research

Similar to spintronics, which attempts to use electron spin polarization as the bits (or possibly qubits) in a logic device, valleytronics attempts to use a combination of the spin and "valleys&...
13
votes
0answers
58 views

How to set up a local server for iQmol on macOS?

I'm still trying to set up iQmol as a tool to submit calculations to Q-Chem on our lab machines to make access to it easier for OChem students. Unfortunately it is not working properly "from the ...

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