Table 5.

Bond lengths in Å and angles in degrees for the butanone (BTON) and propionaldehyde (PALD) gauche and cis conformations from QM optimizations at the MP2/6-31G(d) level of theory and Drude calculations.

	Atoms	QM	MM	MM-QM
BTON gauche	C1-O1	1.23	1.22	−0.01
	C2-C1	1.52	1.50	−0.02
	C1-C3	1.52	1.50	−0.02
	C3-C4	1.53	1.54	0.01
	C2-C1-O	121.21	121.55	0.34
	O-C1-C3	121.47	121.33	−0.14
	C2-C1-C3	117.32	117.11	−0.21
	C1-C3-C4	113.13	112.56	−0.57
BTON cis	C1-O1	1.23	1.22	−0.01
	C2-C1	1.51	1.50	−0.01
	C1-C3	1.52	1.50	−0.02
	C3-C4	1.52	1.54	0.02
	C2-C1-O	121.64	121.36	−0.28
	O-C1-C3	121.69	122.30	0.61
	C2-C1-C3	116.67	116.34	−0.33
	C1-C3-C4	113.08	114.90	1.82
PALD gauche	C-O	1.22	1.22	0.00
	C-CB	1.51	1.50	−0.01
	CB-CG	1.53	1.53	0.000
	C-HA	1.11	1.10	−0.01
	HA-C-O	120.35	119.23	−1.12
	HA-C-CB	114.94	117.45	2.51
	CB-C-O	124.70	123.33	−1.37
	C-CB-CG	111.06	111.28	0.22
PALD cis	C-O	1.22	1.22	0.00
	C-CB	1.51	1.50	−0.01
	CB-CG	1.52	1.54	0.02
	C-HA	1.11	1.10	−0.01
	HA-C-O	120.28	118.96	−1.32
	HA-C-CB	115.51	116.98	1.47
	CB-C-O	124.22	124.06	−0.16
	C-CB-CG	113.10	114.30	1.2