Gaussian External Format

Overview

Property Value
File extension .ein
Coordinate units Bohr (atomic units)
Supports periodicity No
Supports charge/spin Yes
Format hint ein

Specification

Note

Reference

The Gaussian external format is used for interfacing Gaussian with external programs. It uses fixed-format input with atomic coordinates in atomic units (Bohr).

Format Structure

Line 1: Header (fixed format 4i10) - Number of atoms - Run mode (ignored when reading) - Total charge - Number of unpaired electrons (spin)

Atom lines: Fixed format (i10,4f20.12) - Atomic number (positive integer) - x, y, z coordinates in Bohr - Scalar quantity (typically partial charge, ignored when reading)

Example

Caffeine molecule:

        24         1         0         0
         6      2.027996941030      0.092313100971     -0.143108928077      0.000000000000
         7      4.750109032883      0.023734954927     -0.143241208877      0.000000000000
         6      6.334341685252      2.070988200950     -0.142353037792      0.000000000000
         7      8.728605263543      1.380028892063     -0.142655393906      0.000000000000
         6      8.653186310426     -1.193248402810     -0.142315243278      0.000000000000
         6      6.238570386230     -2.083535979669     -0.142182962479      0.000000000000
         6      5.632667631585     -4.699502178348     -0.139405065684      0.000000000000
         8      3.449316339873     -5.480922657010     -0.143184517105      0.000000000000
         7      7.775087464402     -6.244277357876     -0.131071375299      0.000000000000
         6     10.302293246446     -5.397396780594     -0.136721655174      0.000000000000
         8     12.074100072866     -6.915734697428     -0.136664963403      0.000000000000
         7     10.700382864677     -2.790784724183     -0.141483763966      0.000000000000
         6     13.245975677887     -1.769690333624     -0.142182962479      0.000000000000
         6      7.408915313425     -8.959057313972     -0.116369309269      0.000000000000
         1      1.387020877193      2.055757011721     -0.141786120079      0.000000000000
         1      1.346221699097     -0.863566855309      1.555905663964      0.000000000000
         1      1.346240596354     -0.861336978970     -1.843408533601      0.000000000000
         1      5.655967949599      4.001720959646     -0.141313688652      0.000000000000
         1     14.674305959118     -3.262309083535     -0.143449078705      0.000000000000
         1     13.508968805056     -0.608151528241      1.548989267863      0.000000000000
         1     13.507797175115     -0.606148418987     -1.832145768365      0.000000000000
         1      5.414083058620     -9.492394601323     -0.110227700709      0.000000000000
         1      8.319196188304     -9.749472887017      1.565392087032      0.000000000000
         1      8.315114380769     -9.768540219438     -1.791082028670      0.000000000000

Limitations

The following features are currently not supported:

  • Run mode (second integer in header) is dropped when reading
  • Scalar atomic quantities (fourth column) are not preserved

Note

Feel free to contribute support for missing features or bring missing features to our attention by opening an issue.