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. 2019 May 28;4(5):9271–9283. doi: 10.1021/acsomega.8b03364

Table 5. Calculated and Experimental Fundamental Frequencies of Cyclobutadiene (Unit in cm–1)a.

no. sym. exp. Eckart calc. SD calc. err. (%) active action
1 b2g 53183 505.7 505.3 –4.8 Raman CH OPLA deform
2 b3u 56986 556.5 556.9 –2.1 IR CH OPLA
3 b2u 71986 709.9 710.0 –1.4 IR ring deform
4 b3g 72383 827.8 827.6 14.5 Raman ring deform
5 ag 98983 935.0 935.1 –5.5 Raman CH deform
6 b1u 102886 1002.1 1002.2 –2.5 IR CH deform
7 ag 105983 1093.7 1093.6 3.2 Raman CH deform
8 b3g   1121.9 1121.8   Raman C–C stretch
9 b2u 124286 1198.8 1198.8 –3.5 IR C–H deform
10 ag 167883 1611.0 1611.1 –4.0 Raman C=C stretch
11 b3g 309383 3121.4 3121.3 0.9 Raman CH stretch
12 b2u 310584,86 3139.3 3139.3 1.0 IR CH stretch
13 b1u 312485,86 3159.7 3159.9 1.1 IR CH stretch
14 ag 314083 3172.6 3172.7 1.0 Raman CH stretch
a

The data in the SD calc. column are calculated using the second derivative of the MD trajectory.