Questions tagged [wavefunctions]

Refers to a mathematical description of a quantum state of a system.

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11
votes
1answer
314 views

What is the minimum basis set one should use?

If I'm interested in getting an answer that is minimally correct what is the minimum basis set level I should use? (i.e. anything less would be much less reliable) Obviously this depends on the ...
3
votes
0answers
18 views

How to get energy eigenstates using plane wave basis wavefunction .hdf5 output from Quantum ESPRESSO?

When compiled with the HDF5 flag on, Quantum ESPRESSO (QE) saves wavefunctions in the .save folder. At each k-point, we have an $m\times n$ matrix, where $m$ are the complex number entries of ...
8
votes
0answers
57 views

Visualizing wavefunctions in real space

I would like to generate wavefunctions as functions of spatial coordinates (X, Y, Z) using Gaussian G09 and then visualize them. How might I go about doing this? I am using Linux and my preferred ...
11
votes
1answer
164 views

How to use wavefunctions/density to determine which orbitals lead to edge states?

I have a large matrix for a 1D zigzag edge model of an otherwise $3\times 3$ tight-binding Hamiltonian (3 basis functions, each corresponding to an atomic orbital), involving the variable $k_x$. The ...
12
votes
1answer
133 views

How to numerically solve real-space 1D time-independent Schrodinger equation using 2D momentum-space Hamiltonian?

Consider the usual simple 2-level graphene Hamiltonian with mass in momentum-space where: $$ H(k,V)=-t \sum_{\delta} [\cos(k\cdot\delta)\sigma_x-\sin(k\cdot\delta)\sigma_y+V\sigma_z], $$ where $t$ is ...
5
votes
0answers
60 views

Wavefunction magnitudes being degenerate everywhere on parameter space even though energy degeneracies occur at isolated points?

Cross-posted here: https://physics.stackexchange.com/questions/635887/wavefunction-magnitudes-being-degenerate-everywhere-on-parameter-space-even-thou Consider the usual simple 2-level gapless ...
5
votes
0answers
104 views

How can I calculate and plot the molecular orbitals (MO's) from the Gaussian wavefunction file?

This a follow-up question to my previous question. And as per the answer one could create M.O orbitals from the primitives. As a new user of Gaussian, is there any method (or algorithm) to followed so ...
7
votes
1answer
83 views

How do I interpret the Gaussian16 wavefunction file?

I'm new to gaussian16. The wave function file that I obtain as a result of the "Energy" calculation. It consists of five distinct parts : PART 1 : ...
16
votes
1answer
1k views

Does the Schrödinger equation have unique solutions?

I am learning DFT and the Hohenberg Kohn Theorem of Existence. It says that there is a one-to-one correspondence between the external potential and the density. However the proofs that I have seen ...
24
votes
2answers
223 views

How to overcome the exponential wall encountered in full configurational interaction methods?

Similar to how a molecular orbital, also known as a 1-electron wavefunction, can be represented with a linear combination of “basis” functions, e.g., atomic orbitals (LCAO): $$\Phi(\mathbf{r})=\sum_i^...