Please use ChatGPT to explore a thematic series of questions within the scope of computational chemistry and follow up with further inquiries about any unfamiliar terms  ( except homework )

https://chat.openai.com/share/86e9fbec-fa95-4edd-868e-3aaee50ace50

 

•Use Gaussian or WebMO to calculate the Electron Affinity of Helium、Neon、Argon, by

using B3LYP、MP2 and M062X theoretical methods with cc-pVTZ、aug-cc-pVTZ、d-aug-cc-pVTZ

 

 

kcal/mole	B3LYP/cc-pVTZ	aug-cc-pVTZ	d-aug-cc-pVTZ	real value
He	-376.8	-61.7	-10.1	-12.0
Ne	-630.0	-127.5	-28.4	-27.7
Ar	-302.7	-72.2	no result	-23.2
	MP2\cc-pVTZ	aug-cc-pVTZ	d-aug-cc-pVTZ
He	-394.5	-68.3	-13.2
Ne	-672.0	-141.3	-33.4
Ar	-330.7	-77.8	no result
	M062X\cc-pVTZ	aug-cc-pVTZ	d-aug-cc-pVTZ
He	-367.4	-62.6	-10.7
Ne	-634.6	-87.3	-31.8
Ar	-301.1	-72.8	no result

 

The comparison of absolute errors is as follows

 

B3LYP

MP2

M062X

 

Try to add an additional set of diffuse functions for the s orbital of He, and the s and p orbitals of Ne and Ar. ( in the 6-31G basis set )

B3LYP/6-31G(hartree)				EA(hartree)	EA(kcal/mol)	實際值	絕對誤差
He	-2.90705	He-	-1.58456	-1.32249	-829.9	-12.0	-817.9
Ne	-128.89436	Ne-	-127.28624	-1.60812	-1009.1	-27.7	3539.8
Ar	-527.51714	Ar-	-527.0	-0.52875	-331.8	-23.2	-308.6
(+diffuse function)				EA(hartree)	EA(kcal/mol)	實際值	絕對誤差
He	-2.90911	He-	-2.74585	-0.16326	-102.4	-12.0	-90.5
Ne	-128.91611	Ne-	-127.28624	-1.62987	-1022.8	-27.7	-995.0
Ar	-527.51714	Ar-	-526.98839	-0.52875	-331.8	-23.2	-308.6

 

 

Optimize the H₃⁺ molecule

	H	H2	H2+	H3+	Dissociation energy
energy(hartree)	-0.49982	-1.16377	-0.5309	-1.34174	-0.14689
energy(kcal/mol)	-313.6	-730.3	-333.1	-842.0	-92.2

 

**Dissociation energy** of the molecule, which is the energy required to break the bond and separate the atoms, in **hartree** and **kcal/mol** units.

 

 

 

Reference:inorganic chemistry gary l. miessler paul j. fischer donald a. tarr Edition, 5