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

Table 3

Calculated ground-state rotational constants of propynal (HCCCHO) in various models and basis sets.

Model		Basis set	𝐴0 (MHz)	𝐵0 (MHz)	𝐶0 (MHz)
DFT	B3LYP	6-31+g(d, p)	68098.21	4784.41	4463.15
	B3LYP	6-31++g(d, 2p)	68256.89	4782.68	4462.32
	B3LYP	6-311++g(d, 2p)	69124.41	4816.87	4495.94
	B3PW91	6-31g	66270.21	4767.54	4440.57
	B3PW91	6-31++g(d, 2p)	68576.97	4791.35	4471.19
	B3PW91	6-311++g(d, 2p)	69756.37	4820.39	4501.66
	MPW1PW91	6-31g	66636.15	4783.87	4456.38
	MPW1PW91	6-31++g(d, 2p)	69083.92	4804.28	4484.75
	MPW1PW91	6-311++g(d, 2p)	70009.21	4833.54	4514.27
	PBEPBE	6-311g	64622.84	4749.88	4417.10
	PBEPBE	6-311++g(d, 2p)	68197.19	4764.26	4448.29
	PBE1PBE	6-31++g(d, 2p)	64197.26	4750.79	4417.61
Expt.^f			68035.25	4826.22	4499.59

^fThis work.