CH₄ (¹A₁)

(²A₁)

EA

AVDZ

MP2(FC)

MP2(full)

CCSD(T)-FC

CCSD(T)-full

−40.367726

−40.370821

−40.395779

−40.398714

−40.336495

−40.339566

−40.365759

−40.368668

0.850

0.850

0.817

0.817

AVTZ

MP2(FC)

MP2(full)

CCSD(T)-FC

CCSD(T)-full

−40.414459

−40.432995

−40.440894

−40.460316

−40.388297

−40.406794

−40.415825

−40.435189

0.712

0.713

0.682

0.683

AVQZ

MP2(FC)

MP2(full)

CCSD(T)-FC

CCSD(T)-full

−40.427405

−40.456603

−40.451691

−40.482485

−40.404025

−40.433197

−40.429318

−40.460039

0.636

0.637

0.608

0.610

AV5Z

MP2(FC)

MP2(full)

CCSD(T)-FC

CCSD(T)-full

−40.431903

−40.467144

−40.454875

−40.492067

−40.416125

−40.451340

−40.439863

−40.477013

0.429

0.430

0.408

0.409

AV6Z

MP2(FC)

MP2(full)

CCSD(T)-FC

CCSD(T)-full

−40.433700

−40.473910

−40.455948

−40.498371

−40.414988

−40.455160

−40.438082

−40.480470

0.509

0.510

0.486

0.487

AV6Z+diff

MP2(FC)

MP2(full)

CCSD(T)-FC

CCSD(T)-full^a

−40.433700

−40.473913

−40.455950

−40.498377

−40.414995

−40.455164

−40.438086

−40.480474

0.509

0.510

0.486

0.487

Previous values^b

MP2/

6-31G(d, p)

6-311++G(2d, 2p)

6-311++G(3df, 3pd)

MP4/

6-31G(d, p)

6-311G(2df, p)

6-311++G(2d, 2p)

QCISD(T)/6-311G(d, p)

QCISD(T)/6-31+G(d)

MP2/CBS-B3

G1, G2, G2MP2

−40.318083

−40.334783

−40.366577

−40.388655

−40.405682

−40.105892

−40.298017

−40.332108

−40.166351

−40.369066

6.1

1.0

0.9

6.0

3.7

1.0

3.7

2.3

1.2

1.2, 1.2, 1.2