MP2

CH₄

AVDZ

1.0986, 1.0975

1.1021, 1.1011

AVTZ

1.0861, 1.0841

1.0888, 1.0867

AVQZ

1.0848, 1.0823

1.0863, 1.0840

AV5Z

1.0846, 1.0807

1.0862, 1.0831^b

AV6Z

1.0845, 1.0807

1.0859, 1.0828^c

AV6Z+diff

1.0845, 1.0807

1.0859, 1.0828^d

CBS

1.0843, 1.0807

1.0858, 1.0827

MP2/6-311++G(2d, 2p)

MP2/6-311++G(3df, 3pd)

1.0870^a

1.0850^a

1.0910^a

1.0880^a