Normal mode analysis (FREQ)

In GRRM17 program, you can perform a normal mode analysis (harmonic vibrational frequency calculation) by specifying the job type "FREQ". A standard normal mode analysis is done by diagonalization of the mass-weighted Hessian matrix. Components of translation and rotation of the entire system are projected out before the diagonalization.

An input file for formaldehyde is:

FREQ/MP2/6-31G

0 1
C         -0.000000000000         -0.000000000000         -0.549482561269
O          0.000000000000          0.000000000000          0.708343639882
H          0.000000000000          0.934113144104         -1.131025039307
H         -0.000000000000         -0.934113144104         -1.131025039307
Options
Temperature = 298.15
Pressure = 1.0
Symmetry number = 2

Harmonic frequencies and normal modes will be printed at the bottom of xxx.log file. The Gibbs free energy assuming Harmonic oscillator, rigid rotor, ideal gas approximations will also be computed. Although GRRM17 will assign the symmetry number automatically, users can specify it manually. An example of the output is shown below.

Normal Mode Analysis at Stationary Point
=========================================================================

FREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQF
Geometry (Origin = Center of Mass, Axes = Principal Axis), SYMMETRY = C2v
C          0.000000000000         -0.000000000000         -0.631332224508
O          0.000000000000          0.000000000000          0.626493976643
H          0.000000000000         -0.934113144104         -1.212874702546
H          0.000000000000          0.934113144104         -1.212874702546

1               2               3
Freq.  :          1197.42908695   1283.52009214   1515.48659989
C  - x :          -0.1709840977   -0.0000000000   -0.0000000000
C  - y :           0.0000000000   -0.1444298634    0.0000000000
C  - z :          -0.0000000000   -0.0000000000   -0.2456368276
O  - x :           0.0405571750    0.0000000000    0.0000000000
O  - y :          -0.0000000000    0.0757143551   -0.0000000000
O  - z :          -0.0000000000    0.0000000000    0.2629348534
H  - x :           0.6961032804    0.0000000000    0.0000000000
H  - y :          -0.0000000000    0.2590299404    0.2139066140
H  - z :           0.0000000000   -0.6477709205   -0.6241056532
H  - x :           0.6961032804    0.0000000000   -0.0000000000
H  - y :          -0.0000000000    0.2590299404   -0.2139066140
H  - z :          -0.0000000000    0.6477709205   -0.6241056532

4               5               6
Freq.  :          1680.11803551   3019.78912654   3105.61827592
C  - x :           0.0000000000    0.0000000000    0.0000000000
C  - y :           0.0000000000    0.0000000000    0.1002946008
C  - z :          -0.1910788293    0.0581483034   -0.0000000000
O  - x :          -0.0000000000   -0.0000000000   -0.0000000000
O  - y :          -0.0000000000   -0.0000000000    0.0000125967
O  - z :           0.0738795606    0.0000720620    0.0000000000
H  - x :          -0.0000000000   -0.0000000000   -0.0000000000
H  - y :          -0.4184163879   -0.6148755105   -0.5971952741
H  - z :           0.5513103229   -0.3467527813   -0.3719251282
H  - x :          -0.0000000000   -0.0000000000   -0.0000000000
H  - y :           0.4184163879    0.6148755105   -0.5971952741
H  - z :           0.5513103229   -0.3467527813    0.3719251282

Thermochemistry at  298.150 K,    1.000 Atm
E(el)         =  -114.028691241420
ZPVE          =     0.026886845139
Enthalpie(0K) =  -114.001804396281
E(tr)         =     0.001416284860
E(rot)        =     0.001416284860
E(vib)        =     0.026922793795
H-E(el)       =     0.030699553420
Enthalpie     =  -113.997991688000
S(el)         =     0.000000000000
S(tr)         =     0.000057577109
S(rot)        =     0.000025730302 (Symmetry number = 2)
S(vib)        =     0.000000139497
G-E(el)       =     0.005819857897
Free Energy   =  -114.022871383523

FREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQFREQF

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Updated At:Aug. 4, 2020, 2:02 p.m.