Let's say I want to make k-point convergence test for graphite. And let's say it converges at 12x12x4. Do I first need to do a k-point convergence test for equal k-points on xyz directions then make another k-point convergence test with changing k-point only along z-direction? I am asking because...

I was trying to calculate the hyperpolarizability $\beta$ of a cluster of two water molecules in Gaussian16 using the route card: #t cam-b3lyp/daug-cc-pvtz Polar nosymm scf=tight int=grid=superfine #t cam-b3lyp/daug-cc-pvtz Polar=doubleNumer nosymm scf=tight int=grid=superfine The files w...