TRANSQT(1)

📦 version 3.4.0, in debian bookworm, ubuntu jammy, ubuntu noble

💖 transqt(1) — PSI COMMANDS FOR UNIX USERS 💖

okay so bestie, welcome to transqt, the glow-up station for your integrals ✨ this is from Psi Release 2.0, last changed 21 March, 1995 (yes she's vintage, she's still that girl) 🎀

✨ NAME ✨

transqt — transforms one and two electron integrals over symmetry orbitals into integrals over molecular orbitals. it's giving glow-up montage for integrals, fr fr 💅

🌸 DESCRIPTION 🌸

okay so here's the tea ☕ the program transqt reads molecular orbital coefficients from FILE30 and uses them to transform the one and two electron integrals contained in FILE33, FILE35, FILE36, and FILE37 to integrals over molecular orbitals. iconic behavior, no cap 👑

but wait — no integrals involving frozen occupied and unoccupied orbitals (as determined from user input) are transformed. nope, they're not invited to the party 🙈 and because of that, the program must be re-run whenever the user-input frozen orbital arrays are changed. like, every single time. keep up bestie 💀

the program uses a straightforward four single-index transformation algorithm, modified to use matrix multiplications for each quarter-transform. the way she multitasks?? main character energy honestly 🌈

additionally, restricted transformations have been implemented when an MP2 or MP2-R12/A energy is desired. she's versatile like that 🦋

further, the program is capable of backtransforming the Lagrangian and one- and two-particle density matrices from correlated calculations. 🔥 this assumes that the terms involving core orbitals are present, but those involving frozen virtual orbitals are not. so like, core orbitals: present 💅 frozen virtuals: not present, they ghosted 🫥

📚 REFERENCES 📚

general integral transformation methods, aka the required reading 📖:

  1. S. Wilson, "Four-Index Transformations," in Methods of Computationsl Chemistry, Vol. 1, S. Wilson, ed., Plenum Press, 1987.

TRANSQT references, the actual receipts 🧾:

  1. C. D. Sherrill, "Computational Algorithms for Large-Scale Full and Multi-Reference Configuration Interaction Wavefunctions", Ph.D. Dissertation, University of Georgia, 1996.

🎀 FILES REQUIRED 🎀

like she literally cannot function without these, they're her emotional support files 😭

  • input.dat
  • FILE30
  • FILE33
  • FILE35
  • FILE36
  • FILE37

⭐ FILES GENERATED ⭐

the babies she makes 💖

  • output.dat
  • FILE71 (one-electron integrals)
  • FILE72 (two-electron integrals)
bestie this is only part 1, there's more coming so don't go anywhere 👀

💖 INPUT OPTIONS 💖

ok bestie, here's the lineup of command-line options you can throw at this thing:

  • -quiet — literally gives the same result as setting PRINT=0. no notes.
  • -backtr — runs a back-transformation, same effect as BACKTRANS=TRUE.
  • -mp2r12a type — tells TRANSQT to transform the non-standard two-electron integrals you need for MP2-R12/A calculations. ⚠️ heads up: program CR12INTS must be run before the transformation happens, no skipping. type should take values from 0 to 2, where 0 = regular ERIs and one-electron integrals, 1 = two-electron integrals over the r12 operator, and 2 = two-electron integrals over the [r12,T1] operator. so to get a complete set of integrals, TRANSQT needs to be run three whole times. yes, three. it's giving commitment.

Additional input gets read from the file input.dat. these are the keywords that are valid:

  • BACKTRANS = boolean — set this to TRUE for a back-transformation of the Lagrangian and the one- and two-particle density matrices from the MO basis to the AO basis. it assumes these quantities are given in terms of the correlated orbital order. TRANSQT will rearrange them into the Pitzer order but with frozen virtuals at the top — and yes, this happens during the pre-sort for the two-pdm.
  • CHECK_C_ORTHONORM = boolean — if TRUE, then it checks the orthonormality of the SCF coefficient matrix. vibe check for your coefficients, basically. 🫶
  • MEMORY = (real MB) — the amount of core memory to be used, in megabytes.
  • WFN = string — this is the type of wavefunction you ultimately want. if the value is set to MP2, then only a restricted transformation is performed, producing the integrals necessary for evaluating the MP2 energy. otherwise, a full transformation is carried out. the default is CCSD.
  • PRINT = integer — controls the verbosity of the printing information. a print value of 0 gives minimal info, while 5 gives debugging information. 🚨 do NOT use print levels above 3 for more than 20 basis functions. the default is 0.
  • FROZEN_DOCC = integer_vector — array giving the number of doubly occupied orbitals to be frozen per irreducible representation, using Cotton ordering. the default is a zero array.
  • FROZEN_UOCC = integer_vector — array giving the number of virtual molecular orbitals per irrep to be deleted from the transformed integrals. the default is a zero array.
  • DELETE_AO = boolean — if TRUE, then the AO integrals will be deleted after the transformation. the default is TRUE.
  • DELETE_TPDM = boolean — if TRUE, then the MO-basis two-particle density matrix will be deleted after a back-transformation. the default is TRUE.
  • FREEZE_CORE = boolean — if this is true, then the transformed one- and two-electron integrals involving frozen core orbitals will not be obtained or written out. the transformed one-electron integrals will incorporate the effects of the frozen electrons (i.e. the one-electron operator h(i) will become the frozen core operator h’(i)), and the frozen core energy will be obtained — it gets written out as the first word of the one-electron integral output file. if FREEZE_CORE is false, then the frozen core orbitals will be included in the transformation, and the frozen core energy will be set to zero.
  • MAX_BUCKETS = integer — maximum number of buckets to use during the Yoshimine sort. the default is 199.
  • MOORDER = integer_vector — specifies a molecular orbital reordering vector. it will only be used if REORDER = YES. this vector contains first the ordering for the orbitals in the first irreducible representation, then the second, and so on. the first orbital of each irreducible representation is numbered 1. there is no default. this reordering affects the SCF coefficient matrix BEFORE the transformation; the post-transform order is given by a different array.
  • REORDER = boolean — the molecular orbitals will be reordered if this is true, in which case the MOORDER parameter must be present. the default is false. this has nothing to do with the reordering done AFTER the transformation (the one that goes to a more convenient order for correlated procedures).
  • PRINT_MOS = boolean — if TRUE, the SCF coefficient matrix is written to output. the default is FALSE.
  • PRINT_REORDER = boolean — if true, prints the reordering array which maps Pitzer-ordered orbitals to correlated order. note that this is not the same as the MOORDER array, which has to do with reordering BEFORE the transformation.
  • S_FILE = integer — if USE_IWL=TRUE, this gives the file number for the overlap integrals. the default is 35.
  • T_FILE = integer — if USE_IWL=TRUE, this gives the file number for the kinetic energy integrals. the default is 36.
  • V_FILE = integer — if USE_IWL=TRUE, this gives the file number for the nuclear attraction integrals. the default is 37.
  • AO_TEI_FILE = integer — gives the file number for the SO two-electron integrals to be read in for transforming. the default is 33.
  • J_FILE = integer — gives the file number for the intermediate file containing the half-transformed two-electron integrals. the default value is 91.
  • KEEP_J = boolean — if this is true, then the half-transformed integrals will not be deleted when the transformation is complete. the default is FALSE.
  • M_FILE = integer — gives the file number for the intermediate file containing the fully transformed two-electron integrals. the default value is 72.
  • FIRST_TMP_FILE = integer — gives the number of the first temp file to be used during the Yoshimine sorts. default is 100.
  • LAG_IN_FILE = integer — this is the unit number for the MO Lagrangian which is to be read in during backtransformations. it's expected that the Lagrangian is stored on disk in binary format in a matrix of dimensions (nmo - nfzv)*(nmo-nfzv). the Lagrangian is symmetrized and then backtransformed and written after the AO one-particle density matrix in OPDM_OUT_FILE.
  • OPDM_IN_FILE = integer — the unit number for the MO one-particle density matrix to be read in during backtransformations. the one-pdm is in binary format and has dimensions nmo by nmo.
  • OPDM_OUT_FILE = integer — the unit number to which the AO one-particle density matrix will be written out. only the lower triangle is written. the AO Lagrangian will be written just after the AO one-pdm, again in lower-triangle format.
  • PRESORT_FILE = integer — gives the file number for the intermediate file containing the presorted SO-basis two-electron integrals. the default is 41.
  • KEEP_PRESORT = boolean — if this is true, then the presorted SO-basis two-electron integrals will not be deleted when the transformation is complete. the default is FALSE.
  • SORTED_OEI_FILE = integer — gives the file number for the final, sorted one electron integrals. the default is 71.
  • SORTED_TEI_FILE = integer — gives the file number for the final, sorted two electron integrals. the default is 72.
  • TPDM_ADD_REF = boolean — if TRUE, then the program will automatically add the contributions of the single determinant reference to the two-particle density matrix. the default is TRUE for wfn = QVCCD and FALSE otherwise.
  • TPDM_FILE = integer — gives the file number for the two-particle density matrix which is to be back-transformed if BACKTRANS=TRUE. the default is 77.
  • TOLERANCE = integer — gives the exponent of the cutoff value for the elimination of two-electron integrals from the list of those written to disk. the default is 14, giving a cutoff of 1e-14.
  • PRINT_TE_INTEGRALS = boolean — if this is true, then the fully-transformed two-electron integrals will be written to output.dat. the default is FALSE, and this should not be set to TRUE for any but the smallest basis sets (e.g. fewer than 10 functions).
  • PRINT_OE_INTEGRALS = boolean — if this is true, then the fully-transformed one-electron integrals will be written to output.dat. the default is FALSE, and this should not be set to true for any but very small basis sets (e.g. fewer than 20 functions).
and that's the whole page, bestie 💅 we ate, no crumbs left.

✨ this iconic lil manual page is from Psi Release 2.0, and its last change was on 21 March, 1995 — vintage queen behavior, we stan a classic 🎀💖

📦 where this page comes from