CH3-O-C(=O)NH2





















 




Nitrogen

Nuclear Quadrupole Coupling Constants


in Methyl Carbamate


 








 








 








Nitrogen nqcc's in methyl carbamate were determined by Bakri et al. [1].  An reBO structure was derived by Demaison et al. [2].  Calculation was made here of the nqcc's on this reBO structure and on an ropt structure given by MP2/6-311+G(3df,3pd) optimization.  These calculated and experimental nqcc's are compared in Table 1.    Structure parameters are given here in Z-matrix format.  Rotational constants are given in Table 2.

 








In Table 1, subscripts a,b,c refer to the principal axes of the inertia tensor; x,y,z to the principal axes of the nqcc tensor.  ETA = (Xxx - Xyy)/Xzz.  RMS is the root mean square difference between calculated and experimental diagonal nqcc's (percentage of the average of the magnitudes of the experimental nqcc's).  RSD is the calibration residual standard deviation of the B3PW91/6-311+G(df,pd) model for calculation of the nitrogen efg's/nqcc's.


 








 








 








Table 1. 14N nqcc's in Methyl Carbamate (MHz).  Calculation was made reBO on and ropt structures.
 










Calc /reBO
Calc /ropt
Expt. [1]
 








Xaa
2.148
2.219
2.28325(71)

Xbb
2.045
2.041
2.01283(75)

Xcc -
 4.192
 -
 4.260 -
 4.29609(75)

Xab
 -
 0.209
 -
 0.228



Xac
0.952
 - 0.686



Xbc
 -
 0.478
0.511












RMS
0.100 (3.5 %)
0.046 (1.6 %)



RSD
0.030 (1.3 %)
0.030 (1.3 %)












Xxx
1.886
1.885



Xyy
2.477
2.483



Xzz -
 4.363
 - 4.368



ETA
0.135
0.137













 








 













Table 2.  Methyl Carbamate.  Rotational constants (MHz).
 





Calc /reBO Calc. ropt     Expt. [1]






A 10749.7
 10719.3 10719.3715(15)

B   4450.1
   4437.1
   4399.14788(66)

C   3214.5
   3204.5
   3182.88655(68)


 








 








[1] B.Bakri, J.Demaison, I.Kleiner, L.Margulčs, H.Mřllendal, D.Petitprez, and G.Wlodarczak, J.Mol.Spectrosc. 215,312(2002).

[2] J.Demaison, A.G.Császár, I.Kleiner, and H.Mřllendal, J.Phys.Chem. A 111,2574(2007).

 








M.B.Shundalov, G.A.Pitsevich, M.A.Ksenofontov, and D.S.Umreiko, J.App.Spectrosc. 76(3),325(2009).

P.Groner, M.Winnewisser, I.R.Medvedev, F.C.DeLucia, E.Herbst, and K.V.L.N.Sastry, ApJS 169,28(2007).

R.A.Kydd and A.Rauk, J.Mol.Struct. 77,227(1981).

 








 







Ethyl Carbamate I
 Ethyl Carbamate II





 








 








Table of Contents




Molecules/Nitrogen




 








 













methylcarbamate.html






Last Modified 16 Feb 2012