W8

Reference: Computational Chemistry Comparison and Benchmark DataBase

•Calculate the structure and frequencies of XH_n (X = H~Ne) by using B3LYP theoretical method with 6-31+G(d,p) then compare with the experimental values.

frequency	H2	exp	error	LiH	exp	error	BeH2	exp	error	BH3	exp	error	CH4	exp	error	NH3	exp	error	H2O	exp	error	HF	exp	error
Unit: cm^-1	4465.7	4161.2	304.48	1402.0	1359.7	42.3	735.9	697.9	38.0	1157.6	1147.5	10.1	1347.3	1306.0	41.3	1000.3	950.0	50.3	1603.4	1595.0	8.4	4069.8	3961.4	108.37
							735.9			1205.2	1196.7	8.5	1347.3			1673.6	1627.0	46.6	3809.6	3657.0	152.6
							2038.4			1205.2			1347.3			1673.6			3931.5	3756.0	175.5
							2260.6	2159.1	101.5	2576.8	2601.6	-24.8	1563.8	1534.0	29.8	3484.7	3337.0	147.7
										2704.4			1563.8			3627.6	3444.0	183.6
										2704.4			3037.1	2917	120.1	3627.6
													3150.1	3019.0	131.1
													3150.1
													3150.1

•Calculate the single point energy of XH_n (X = H~Ne) by using CCSD(T) theoretical method with aug-cc-pVTZ ( the structure obtained from the previous homework ), and then use those energy to calculate the standard enthalpy of formation (ΔH°_f) then compare with the experimental values.

unit : kcal/mol	Exp	CCSDT/aug-cc-pVTZ of B3LYP/6-31+G**	CCSDT/aug-cc-pVTZ of B3LYP/aptz	CCSDT/aug-cc-pVTZ of MP2/6-31+G**	CCSDT/aug-cc-pVTZ of MP2/aptz
H2	0.0	1.0	1.0	1.2	1.1
LiH	33.6	34.3	34.4	34.3	34.3
BeH2	30.0	42.3	42.4	42.4	42.4
BH3	21.0	27.3	27.3	27.5	27.4
CH4	-17.8	-11.6	-11.3	-11.4	-11.3
NH3	-11.0	-4.2	-4.2	-4.1	-4.1
H2O	-57.8	-53.3	-53.3	-53.3	-53.2
HF	-65.3	-63.3	-63.3	-63.3	-63.2

experimental value: Computational Chemistry Comparison and Benchmark DataBase

unit:kcal/mol	CCSDT/aug-cc-pVTZ of B3LYP/6-31+G**	CCSDT/aug-cc-pVTZ of B3LYP/aptz	CCSDT/aug-cc-pVTZ of MP2/6-31+G**	CCSDT/aug-cc-pVTZ of MP2/aptz
MAE	4.975	5.0375	5.075	5.0875

Conclusion : Use different theoretical method and basis set didn't get significant difference

瀏覽數:

友善列印