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bsonghao / Thermal-Field

thermal field coupled cluster method: A new method for finite temperature electronic structure
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Conduct CASSCF calculation in PySCF #18

Open bsonghao opened 2 years ago

bsonghao commented 2 years ago

N2 molecule

  1. Define the number of orbitals in the active space
  2. Conduct ground state CASSCF calculation
  3. Extract Hamiltonian matrix element in the active space

For detail setting, read PySCF manual.

bsonghao commented 2 years ago

c1dbbcc375c987580e5e3d10b4bc1c8f3216a209 implement it

bsonghao commented 2 years ago

image

Question: how to transform the active space 1-electron and 2-electron integral from AO basis to MO basis

bsonghao commented 2 years ago

Do I need to shift the core electron energy in the CC calculation of the model Hamiltonian in CAS?

bsonghao commented 2 years ago

54ddddc087b43b56f7673d2123b4f8a6371a8512 implement the shift of core electron energies image

But after the shift, the zero temperature limit shift does not match GS energy, requires further scrutiny on the energy shift

bsonghao commented 2 years ago

7b217cc982f33570cbdfb6af0c04df45384421ef fix the bug on energy shift of core electron contribution image

image image Clearly the thermal curve for CCSD calculation as a function of temperature is unphysical but the converged GS energy seems reasonable