Millimeterwave Spectral Studies of Propynal (HCCCHO) Produced by DC Glow Discharge and Ab Initio DFT Calculation

Table 4

Comparison of the molecular optimized geometry, dipole moment, and total energy of propynal calculated by various methods and basis sets with the experimental values.

Method	Model	Basis set	1H-2C (Å)	2C-3C (Å)	3C-4C (Å)	4C-5H (Å)	4C-6O (Å)	(3C-4C-6O) (in degree)	μ(D)	Energy (a.u)
DFT	B3LYP	6-31+g**	1.059	1.212	1.452	1.114	1.219	123.89	3.141	−190.6240574
	B3LYP	6-31++g(d, 2p)	1.058	1.212	1.452	1.113	1.219	123.94	3.125	−190.6246385
	B3LYP	6-311++g(d, 2p)	1.054	1.204	1.450	1.110	1.211	124.06	3.074	−190.6720249
	B3PW91	6-31g	1.059	1.216	1.441	1.108	1.242	124.38	3.244	−190.4741521
	B3PW91	6-31++g(d, 2p)	1.059	1.212	1.450	1.114	1.216	123.94	3.095	−190.5414422
	B3PW91	6-311++g(d, 2p)	1.056	1.204	1.448	1.112	1.209	124.09	3.038	−190.5861953
	MPW1PW91	6-31g	1.057	1.214	1.439	1.106	1.239	124.32	3.254	−190.4964469
	MPW1PW91	6-31++g(d, 2p)	1.058	1.209	1.449	1.111	1.213	123.90	3.095	−190.565401
	MPW1PW91	6-311++g(d, 2p)	1.055	1.202	1.448	1.110	1.206	124.06	3.042	−190.609715
	PBEPBE	6-311g	1.063	1.219	1.442	1.117	1.253	124.14	3.111	−190.3871779
	PBEPBE	6-311++g(d, 2p)	1.062	1.216	1.449	1.123	1.223	124.10	3.002	−190.4447923
	PBE1PBE	6-31++g(d, 2p)	1.063	1.221	1.441	1.117	1.254	124.06	3.284	−190.3966287
Expt.^g			1.055	1.208	1.444	1.106	1.215	123.80	2.747 ^h

^g[5], ^h[17].