HW_7_ken

•ChatGPT

•Calculate the structures and atomization energies (AE) of XHn (X = H~Ne) by using B3LYP、MP2 theoretical methods with 6-31+G(d,p)、aug-cc-pVTZ then compare with the experimental values.

1. Structures

Bond angle ( degree )

　

H2

LiH

BeH2

BH3

CH4

NH3

H2O

HF

　

B3LYP/6-31+G(d,p)

-

-

180

120

109.5

108.1

105.8

-

　

B3LYP/aug-cc-pVTZ

-

-

180

120

109.5

107.2

105.1

-

　

MP2/6-31+G(d,p)

-

-

180

120

109.5

108.1

105.4

-

　

MP2/aug-cc-pVTZ

-

-

180

120

109.5

106.8

104.1

-

　

實驗值

-

-

180

120

109.5

106.7

104.5

- 

Reference: Atkins' PHYSICAL CHEMISTRY 

 

Bond length (Å)

　

H2

LiH

BeH2

BH3

CH4

NH3

H2O

HF

　

B3LYP/6-31+G(d,p)

0.743

1.614

1.331

1.193

1.093

1.016

0.965

0.928

　

B3LYP/aug-cc-pVTZ

0.743

1.59

1.325

1.188

1.088

1.013

0.962

0.924

　

MP2/6-31+G(d,p)

0.734

1.623

1.328

1.186

1.087

1.012

0.963

0.926

　

MP2/aug-cc-pVTZ

0.737

1.605

1.33

1.187

1.086

1.012

0.961

0.922

　

 實驗值

0.741

1.595

1.326

1.19

1.087

1.012

0.958

0.917

Reference: Atkins' PHYSICAL CHEMISTRY 

Absolute error of bond length (Å) 　 H2 LiH BeH2 BH3 CH4 NH3 H2O HF MAE
　 B3LYP/6-31+G(d,p) 0.002 0.019 0.005 0.003 0.006 0.004 0.007 0.011 0.007
　 B3LYP/aug-cc-pVTZ 0.002 0.005 0.001 0.002 0.001 0.001 0.004 0.007 0.003
　 MP2/6-31+G(d,p) 0.007 0.028 0.002 0.004 0 0 0.005 0.009 0.007
　 MP2/aug-cc-pVTZ 0.004 0.01 0.004 0.003 0.001 0 0.003 0.005 0.004

There is no obvious difference between the two methods, but there are differences in different basic sets

 

2. Atomization energies

Atomization Energy

　

　

　

　

　

　

　

　

unit(kcal/mol)

H2

LiH

BeH2

BH3

CH4

NH3

H2O

HF

B3LYP/6-31+G(d,p)

111.7

57.0

153.7

286.7

422.8

300.1

229.5

138.2

B3LYP/aug-cc-pVTZ

110.1

58.4

150.7

284.7

420.6

300.6

230.5

138.8

MP2/6-31+G(d,p)

101.1

45.1

138.7

269.4

399.3

274.8

220.4

137.0

MP2/aug-cc-pVTZ

103.8

51.8

146.0

275.4

411.3

290.1

232.1

143.3

實驗值

103.3

55.7

149.3

266.8

392.4

276.7

219.4

135.4

Reference: Atkins' PHYSICAL CHEMISTRY 

llhh

Absolute error of atomization energy

unit(kcal/mol)

H2

LiH

BeH2

BH3

CH4

NH3

H2O

HF

MAE

RMSE

　

B3LYP/6-31+G(d,p)

-8.4

-1.3

-4.4

-19.9

-30.3118

-23.3093

-10.1877

-2.74954

12.57982

16.05635

　

B3LYP/aug-cc-pVTZ

-6.9

-2.7

-1.5

-17.9

-28.1622

-23.8731

-11.1856

-3.38759

11.94395

15.31875

　

MP2/6-31+G(d,p)

2.2

10.6

10.6

-2.7

-6.8471

1.983558

-1.05526

-1.61607

4.691977

6.036807

　

MP2/aug-cc-pVTZ

-0.5

3.9

3.3

-8.7

-18.8989

-13.3642

-12.787

-7.89436

8.664215

10.38713

kk

--> MP2/6-31+G(d,p) >   MP2/aug-cc-pVTZ >   B3LYP/aug-cc-pVTZ >   B3LYP/6-31+G(d,p)