The H4 model revisited within the framework of the G-particle-hole Hypervirial equation

► The planar H4 molecular system is accurately studied here. ► All the conformations are calculated with the G-particle-hole Hypervirial method GHV. ► The GHV determines a correlation matrix, instead of the wave-function. ► It is found that the GHV accuracy is higher than that of the SDCI. ► The performance of the GHV method is comparable to the CCSD.