HCCBr
		Deuterium and Bromine
	Nuclear Quadrupole Coupling Constants
		in Bromoacetylene
	The microwave spectrum of bromoacetylene was first studied by Jones et al. [1].  Bromine nqcc's were measured and a substitution structure was determined.  Somewhat more accurate measurements of the bromine nqcc's were made by Porter and Godfrey [2], and subsequently by Bass et al. [3].  The deuterium nqcc was measured by Heineking et al. [4].  A near equilibrium (rmrho) structure was derived by Berry and Harmony [5].
	Calculation was made here of the deuterium and bromine nqcc's on the substitution and near equilibrium structures.  These are compared with the experimental nqcc's in Table 1.   Structure parameters are compared in Table 2.
	Table 1. Deuterium and Bromine nqcc's in HCCBr (MHz).     Calculation was made on the [a] rmrho and [b] rs structures.   Calc. Expt.     2H Xzz 0.2167 [a] 0.2077(18) [4]   0.2241 [b]   79Br Xzz 652.30 [a] 648.113(3) [3] 652.72 [b] 648.099(21) [2] 648.00  [1]   81Br Xzz 544.98 [a] 541.430(1) [3] 545.32 [b] 541.470(20) [2] 541.47  [1]
	The difference between calculated [a] and experimental 2H nqcc's is 9.0 kHz (4.3 %).
	The difference between calculated [a] and experimental [3] 79Br nqcc's is 4.19 MHz (0.65 %).  For 81Br, the difference is 3.55 MHz (0.66 %).
	Table 2.  Structure parameters (Å). rmrho [5] rs [1] HC 1.0608 1.0553 CC 1.2036 1.2038 CBr 1.7908 1.7913
	[1] H.Jones, J.Sheridan, and O.L.Stiefvater, Z.Naturforsch. 32a,866 (1977).
	[2] A.P.Porter and P.D.Godfrey, J.Mol.Spectrosc. 68,492(1977).
	[3] S.M.Bass, R.L.DeLeon and J.S.Muenter, J.Chem.Phys. 92,71 (1990).
	[4] N.Heineking, M.Andolfatto, C.Kruse, W.Eberstein, and H.Dreizler, Z.Naturforsch. 43a,755(1988).
	[5] R.J.Berry and M.D.Harmony, Struct.Chem. 1,49(1989).
	HCCH		HCCF		HCCCl		HCCCH3
	FCCCl		HCCCN		HCCNC		HCCCF3
	Table of Contents
	Molecules/Deuterium
	Molecules/Bromine
	Summary/Acetylenes  Deuterium nqcc's in DCC-X.
						HCCBr.html
						Last Modified 29 May 2003