CINTS(1)

💖 cints(1) 💖

PSI COMMANDS FOR UNIX USERS ✨ bestie, this is the cints page, fresh out of Psi Release 3.0, and we're gonna get you right with it 🫶

🌸 NAME 🌸

cints — the One- and Two-Electron (Derivative) Integrals Program. that's it, that's the whole vibe 💅

✨ DESCRIPTION ✨

okay so listen 👑 the program cints computes (derivative) integrals of some one- and two-electron operators — the ones that show up in quantum chemical theories — over symmetry-adapted cartesian and spherical harmonics Gaussian functions. no cap, that's literally its whole job 🧚

🎀 DOCUMENTATION 🎀

💀 okay babes, plot twist: the man-page is no longer supported. like, at all. the HTML-based documentation is in index.html now. so go read that instead, iykyk 🫶

the relevant files, real quick:

• input.dat — Input file 📥
• FILE30 — Checkpoint file FILE31 😭 (yes, that's what it says, don't come for me)

Input for this program is read from the file input.dat. most of the keywords are not necessary for a routine task — so don't panic, bestie, you don't need to fill out every single one. but here's the full menu of keywords that are valid:

• PRINT = integer — sets the amount of information that gets printed. defaults to 0. like, chill mode. 📝
• CUTOFF = integral — the negative of the exponent of the cutoff imposed on two-electron integrals. default is 15, which means two-electron integrals of greater than 1e-15 magnitude get stored in FILE33. tiny numbers stay in their lane 💅
• S_FILE = integer — the file number to store overlap integrals in. defaults to 35. 🦋
• T_FILE = integer — the file number to store kinetic energy integrals in. defaults to 35. 🌸
• V_FILE = integer — the file number to store nuclear attraction integrals in. defaults to 35. ⭐
• ERI_FILE = integer — the file number to store electron repulsion integrals in. defaults to 33. 🔥

and that's the whole page, bestie!! you ate that 🍓

Psi Release 3.0 — Last change: 04 Jan, 2000 💜 mwah, go compute some integrals, main character 🎀✨