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Read MoreOfficially, 2021 R1 only supports up to RHEL 8.1. Launching 2021 R1 on RHEL 8.4 complaints Downgrading openssl (multiple times needed depending on the current openssl version) can solve the problem However, it is extremely unsafe to stay at old version libs. But we can copy the old version libraries to another folder and upgrade […]
Read MoreRoothaan equation is the matrix version of Hartree-Fock equations. The derivation is direct as follow. Hartree-Fock equation for the \(i^\mathrm{th}\) spatial orbital \(\varphi_{i}\) \(\hat{f}(1)\varphi_{i}(1)=\epsilon_{i}\varphi_{i}(1)\) Given a set of basis functions \(\left\{\chi_{\nu}\right\},\nu=1,2,\dots,m\), the HF orbitals can be expanded as \(\varphi_{i}=\sum_{\nu=1}^{m}{C_{{\nu}i}\chi_{\nu},i=1,2,\dots,m}\) Denote overlap matrix and Fock matrix as follows \(S_{\mu\nu}=\langle\chi_{\mu}|\chi_{\nu}\rangle\) \(F_{\mu\nu}=\left\langle\chi_{\mu}\left|\hat{f}\right|\chi_{\nu}\right\rangle\) HF equations are then transformed into […]
Read MoreRecently, I came across ‘Forbidden’ error several times when I was trying to download files I had uploaded from Mac to my website running Apache2. And I found if the file was generated by Linux and uploaded also from Linux, then everything would be OK. This error is (sometimes) caused by Mac OS Extended Attribute […]
Read MoreThis is my very first personal website. I will share something I think interesting here, such as phonology, Chinese dialects (mainly Xiang, Cantonese, Wu and Changde ones), popular science of mathematics and physics and programming, etc. Visit, comments and sharing are warmly welcomed.
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