colvarsTrajFrequency    200

colvar {
  name length
  distance {
    group1 {
      atomnumbers { 5 22 36 60 81 98 122 148 160 388 404 418 442 463 480 504 530 542}
    }
    group2 {
      atomNumbersRange 558-3813
    }
  }
}

harmonic {
  name lenpot
  colvars length
  centers 50.0
  forceConstant 1.0
}