The flow equation coupled with the White generator to closed-shell molecules

The flow equation defined in terms of the in-medium similarity renormalization group method, coupled with the White generator has been solved for obtaining ground state energy of closed-shell molecules using the Magnus expansion method. The obtained findings for methane, acetylene and formaldehyde from a calculation with a standard basis set are in reasonable agreement with the value from other high-level methods and close to benchmark values in literature. Moreover, it has been shown that the White generator, when a step size of flow parameter Δs∼1, can enable calculation to be converged within the smallest number of steps.