Unanswered Questions
48 questions with no upvoted or accepted answers
22
votes
0
answers
248
views
Is there a software that can do derivatives with respect to user defined vibrational modes?
I'm doing some property calculations that depend on a sum of derivatives of some quantity with respect to normal vibrational modes. I was hoping to find some physical intuition relating the type of ...
- 15.9k
9
votes
0
answers
184
views
How to do parity analysis of band extrema?
To check whether electronic transitions are allowed between valence band maximum (VBM) and conduction band minimum (CBM) as per Laporte's rule, the parity of VBM/CBM is needed to be known. This paper ...
- 939
7
votes
0
answers
46
views
How to determine if hybridization takes place between orbitals in an ab initio calculation using Quantum ESPRESSO?
I'm using Quantum ESPRESSO to determine the electronic properties of systems. Now I want to confirm if hybridization takes place between orbitals. I have generated density of states and projected ...
6
votes
0
answers
105
views
What are the parameters in PySCF's Selected Configuration Interaction code
Dear StackExchange Members,
I'm using the native PySCF implementation of selected configuration interaction (SCI). However, I can't seem to find any documentation detailing the algorithm or various ...
- 20.1k
6
votes
0
answers
77
views
Benchmarking DFT vs Experimental Gaps - Confusion over Fundamental and Optical Gaps
Recently, I've come across discussions about the differences between fundamental (or electronic) bandgaps and optical bandgaps, with the two quantities differing mainly by the electron-hole binding ...
- 1,366
5
votes
0
answers
202
views
Optical properties using ESPRESSO's epsilon.x
Currently I'm using epsilon.x from Quantum ESPRESSO to analyse optical
properties of metallic alloys. I'm getting a wiggling curve for the dielectric function.
For the imaginary part of dielectric ...
- 3,394
5
votes
0
answers
77
views
Can the electron charge density of two material systems be similar?
Broadly given two electron charge density (ECD) fields, is it possible to distinguish between the elements present in both the systems?
Since the ECD does not explicitly present any information on the ...
- 3,770
5
votes
0
answers
86
views
Packages that can model effects of intense electric fields from femtosecond compressed IR and EUV laser pulses on surfaces?
Laser-based and time-resolved ARPES are relatively1 new techniques to study atomic and especially electronic structure (necessarily) near crystal surfaces and of adsorbed 2D materials on those ...
- 2,074
4
votes
0
answers
27
views
Understanding Oxidation States and Magnetic Moments in Multivalent Transition Metal Oxides
I’m reading some papers on using density functional theory (DFT) to study oxidation states in multivalent transition metal oxides, but I’m having difficulty interpreting the oxidation-state ...
4
votes
0
answers
48
views
How to calculate the volume energy loss function (VELF) using Quantum ESPRESSO?
How to calculate the volume energy loss function (VELF)?
Could you please share with a simple example (with related input files, output files and/or plot)?
Any relevant links would also be welcome.
4
votes
0
answers
65
views
Calculating excitonic optical properties with BSE level in VASP
I have been working on 2D material systems and their heterostructures. While calculating BSE excitonic optical properties in VASP, I encountered that the 2D material property is well matched with ...
4
votes
0
answers
28
views
bandstructure calculation of two-dimensional ferrovalley (RuClBr) in quantum espresso
We try to calculate bandstructure of single layer RuClBr reported in fig.4 of 'https://pubs.rsc.org/en/content/articlelanding/2016/pq/d3nr00346a/unauth'. But our obtained bandstructure is not similar ...
4
votes
0
answers
55
views
supercell nscf kpoints for optical properties
I am calculating the optical properties of 200 atoms supercell with quantum espresso. What is the approximate number of the nscf kpoints (nk nk nk)should I start with, to avoid lengthy kpoints ...
- 161
3
votes
0
answers
36
views
How to correctly set the high-symmetry point path block when there are breakpoints in the recommended path?
I watched Dr. Mohan's tutorial video, and the settings he provided are as follows:
...
- 31
3
votes
0
answers
39
views
How to calculate the second order hyperpolarizability gamma using Gaussian16?
Dear StackExchange community,
I'm trying to calculate the second order hyperpolarizability gamma γ (for example mthane) in guassian16 using solvent introduced manuallly .
here is my input
...
- 905