Vibrational states of urea 
up to 650 cm-1 / 935 K 
and vibrational correction factors to the partition function (at the bottom). 
The data can be used for isotopologs 
with 13C or 15N substition with small errors 
with D with small to modest errors. 

The first 8 vibrational states were taken from 
D. J. Tyree, T. W. Chapman, I. R. Medvedev, Z. Kisiel, 2022, J. Mol. Spectrosc., 390, Art. No. 111706
https://doi.org/10.1016/j.jms.2022.111706 
https://ui.adsabs.harvard.edu/abs/2022JMoSp.39011706T/abstract 
The states are complete up to state 8 ! 
The identity of the states is unclear; it it very unlikely that all of them are fundamentals. 
Please do note that the wavenumbers are uncertain to around 10 cm-1; this has a fairly large impact 
especially for the contribution of the lowest state. 

Two presumable fundamentals near 600 cm-1 have been added. 
Please do note that it is not clear if there are additional states in the vicinity of these states. 
Since this becomes less and less clear for higher vibrational states, we refrain from listing 
further one even though several are known. 

The last 2 vibrational states were taken from 
J. Cz. Dobrowolski, R. Kołos, J. Sadlej, A.P. Mazurek, 2002, Vib. Spectrosc., 29, 261–282 
https://doi.org/10.1016/S0924-2031(01)00187-4

The correction factors are (largely) converged to the quoted digits up to 100 K. 
Additional contributions are each less than 0.5 % up to 175 K. 
Thus, caution is advised for higher temperatures.

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mode / E(cm-1)
 1 /   61
 2 /  254
 3 /  267
 4 /  398
 5 /  420
 6 /  453
 7 /  505
 8 /  571
 9 /  616
10 /  636

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T (K)     F(vib)
300.0    2.9022
225.0    2.3594
175.0    1.9711
150.0    1.7915
125.0    1.6251
100.0    1.4928
 75.0    1.3250
 37.5    1.0964
 18.75   1.0093

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