SHELXT: Integrating space group determination and structure solution

Why is this work in the frame?

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

No Canadian affiliation. An affiliation-only frame, the usual design, would never have seen this work. It is one of the works that make the case for inverting the frame.

Full frame distilled prediction

Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

Candidate categories

none

Consensus categories

none

Domain

Candidate signal: noneConsensus signal: none

Study design

Candidate signal: Bench or experimentalConsensus signal: none

Genre

Candidate signal: EmpiricalConsensus signal: Empirical

Teacher disagreement score

0.976

Threshold uncertainty score

0.634

Validation status

machine_predicted_unvalidated · codex-gemma-dda1882f352a

Codex and Gemma teacher scores by category

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Teacher spread

0.243 · how far apart the two teachers sit on this one work

Validation status

score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Abstract

SHELXT is intended for robust routine solution of small molecule crystal structures. It makes the simple but powerful assumption that the structure consists of resolved atoms, but unlike classical direct methods it is not required that the atoms are 'equal'. This enables it to succeed with poor or incomplete data but makes it unsuitable for structures that are twinned, modulated or contain severe (e.g. 'whole molecule') disorder. SHELXT is a dual-space program that starts with a Patterson minimum superposition and iteratively applies the random omit procedure (also used in SHELXD) with data expanded to space group P1, but does not use phase probability relations or solvent flipping. In the SHELX system it will probably obsolete SHELXS but not SHELXD, which is better for large equal-atom and twinned structures. SHELXT reads any legal SHELX format .ins and (HKLF3 or 4) .hkl files. It extracts the Laue group and tries to find space groups in this Laue group and origin shifts to fit the phases from the best P1 solution, and makes an approximate assignment of element types using the elements specified on the SFAC instruction (and maybe a couple more). This is followed by an isotropic refinement and an attempt to assign the absolute structure if the space group is non-centrosymmetric. It is hoped to release SHELXT as part of the SHELX system (http://shelx.uni-ac.gwdg.de/SHELX/index.php) in time for the 2014 Montreal IUCr Meeting.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

The record

Venue

Acta Crystallographica Section A Foundations and Advances

Topic

Machine Learning in Materials Science

Field

Materials Science

Canadian institutions

not available

Funders

not available

Keywords

Group (periodic table)Space (punctuation)Superposition principleCrystallographySimple (philosophy)Atom (system on chip)Element (criminal law)Crystal structureIsotropyPhysicsChemistryComputer scienceQuantum mechanics

Has abstract in OpenAlex

yes

API

/api/v1/works/W2558855463