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IV.C.1. (XIII.D.1.)

Compare vibrational frequencies in CCCBDB for C4H4N2 (Pyrazine)

PBEPBE/3-21G*

Frequency in cm-1
  Calculated   Experimental
Mode Number Symmetry Frequency diff Symmetry Frequency Comment
1 Ag 2988 -67 Ag 3055  
2 Ag 1436 -144 Ag 1580  
3 Ag 1175 -58 Ag 1233  
4 Ag 946 -70 Ag 1016  
5 Ag 578 -24 Ag 602  
6 Au 954 -6 Au 960  
7 Au 283 -67 Au 350  
8 B1g 893 -34 B1g 927  
9 B1u 2964 -48 B1u 3012  
10 B1u 1387 -96 B1u 1483  
11 B1u 1078 -52 B1u 1130  
12 B1u 929 -89 B1u 1018  
13 B2g 955 -28 B2g 983  
14 B2g 744 -12 B2g 756  
15 B2u 2979 -90 B2u 3069  
16 B2u 1336 -75 B2u 1411  
17 B2u 1115 -34 B2u 1149  
18 B2u 997 -66 B2u 1063  
19 B3g 2961 -79 B3g 3040  
20 B3g 1387 -138 B3g 1525  
21 B3g 1291 -55 B3g 1346  
22 B3g 674 -30 B3g 704  
23 B3u 758 -27 B3u 785  
24 B3u 403 -15 B3u 418  
The calculated vibrational frequencies were scaled by 0.9535

See section XIII.C.3 List or set vibrational scaling factors to change the scale factors used here.
See section III.B.3.c Calculate a vibrational scaling factor for a set of molecules to determine the least squares best scaling factor.
See section III.B.3.b List of vibrational scaling factors and their uncertainties for information on where the above scaling factor is from.