What's the eigval difference in the 'EIGVAL_RTTDDFT.OUT' and 'EIGVAL_0.OUT'?

exciting
1

Hi developers,
Why the max eigval in ‘EIGVAL_RTTDDFT.OUT’ is always smaller than value in the ‘EIGVAL_0.OUT’, here is a example of MoS2,
EIGVAL_0.OUT (1.2 MB)
EIGVAL_RTTDDFT.OUT (95.8 KB)
As far as I understand, the number of energy eigvals of each kpoint in ‘EIGVAL_RTTDDFT.OUT’ is equal to the total bands(valence+conduction) and the number in ‘EIGVAL_0.OUT’ is equal to the Hamiltonian size. What’s the connection between them?
Many thanks!

2

Hi cooman-long,
basically, you are right in your assumptions.

In EIGVAL_RTTDDFT.OUT, we print out the KS eigenvalues up to the number of unoccupied states given by nempty. The eigenvalues are printed out this way for all k-points.
In EIGVAL_0.OUT, for each k-point, we diagonalize the Hamiltonian, and print out all its eigenvalues. This means, we print out KS eigenvalues for all possible unoccupied states. That is why max(eigenvalue) in EIGVAL_0.OUT is larger than max(eigenvalue) in EIGVAL_RTTDDFT.OUT.

Best regards,
Ronaldo Rodrigues Pela