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\(normalc\)

Obtain contributions of atoms, bonds, angles, torsions to normal modes, based on a MOLDEN file
Current version: 2026.01 (shared with CC-BY-NC license). See also all python tools
Installation: mkdir $HOME/msxc ; export MSXC=$HOME/msxc ; export PATH=$PATH:$MSXC/bin ; cd $HOME/msxc ; tar xfz $HOME/Download/normalc-2026.tgz
Usage: normalc [-h/--help] File.molf i1 [i2] [i3] [i4] [--version] ------------------------------------------------------------------ The file to be used as input (File.molf) must be in MOLDEN format; name is irrelevant, as long as it contains the data for vibrational frequencies. Options: -h Help function (this message) (or --help) --version Show version number The first integer (i1) needs to be there always, the others (i2, i3, i4) are optional. Depending on how many integers are present, different contributions to the normal modes will be recovered. In all cases, the contributions are ordered with the largest contributions reported first (max. 10 are shown). If only one integer is present, the contributions of that atom to the different normal modes are obtained. Otherwise, the Cartesian displacement vector for a specific coordinate is projected onto each normal mode. i1: contributions of atom i1 to the normal modes are obtained i1 i2: contributions of bond i1-i2 to the normal modes are obtained i1 i2 i3: contributions of angle i1-i2-i3 to the normal modes are obtained i1 i2 i3 i4: contributions of dihedral i1-i2-i3-i4 to the normal modes are obtained The atom contributions are normalized: when summed over all normal modes they add up to 100 %. Additionally, information about the total contribution of that atom to the normal modes is given: Sum of atomic contributions for atom 1: 1.258255 The contributions shown below are normalized. Frequency Contr.(%) -------------------------- 4 720.5 38.6862 1 219.8 23.4843 2 228.5 16.3950 6 1102.3 13.1452 3 476.0 8.2759 5 797.1 0.0134 Average value: 552.21 ( 552.21 weighted sum, 1.00 sum of weights) Other atoms may contribute much more, and a total contribution > 1 may be observed. It is most easily understood for a four-atom complex like [FAl(O2)]0, which has six vibrational frequencies. Sum of atomic contributions for atom 1: 1.258255 Sum of atomic contributions for atom 2: 1.943533 Sum of atomic contributions for atom 3: 1.399106 Sum of atomic contributions for atom 4: 1.399106 ------------------------------------------------------ Sum 6.000000 I.e., the total sum of atomic contributions adds up to the total number of vibrations. For a bond, similar information is shown: The contributions shown below for bond 1-2 are not normalized. Frequency Contr.(%) -------------------------- 6 1102.3 77.9229 4 720.5 60.7826 3 476.0 13.8113 1 219.8 0.0000 2 228.5 0.0000 5 797.1 0.0000 Average value: 893.41 ( 1362.60 weighted sum, 1.53 sum of weights) Note that the contributions of the bonds, angles, dihedrals are not normalized.