Table 1 B3LYP/6-311++G** optimized values of bond lengths (Å) and the F _n coefficient for Thiophene and Chlorothiophenes

Thiophene

1.733

1.733

1.366

1.428

1.366

1.045

1.728

1.728

1.422

1.376

1.421

0.968

A

1.740

1.737

1.364

1.428

1.364

1.047

1.760

1.715

1.419

1.378

1.414

0.973

B

1.732

1.733

1.363

1.424

1.364

1.044

1.681

1.780

1.437

1.341

1.366

0.957

C

1.741

1.735

1.367

1.427

1.362

1.046

1.732

1.743

1.445

1.395

1.383

0.987

D

1.740

1.737

1.362

1.427

1.361

1.048

1.782

1.700

1.385

1.386

1.431

0.984

E

1.745

1.745

1.362

1.429

1.361

1.050

1.750

1.750

1.410

1.379

1.410

0.978

F

1.730

1.730

1.363

1.433

1.363

1.051

1.733

1.734

1.413

1.387

1.412

0.982

G

1.738

1.734

1.367

1.435

1.360

1.052

1.754

1.728

1.415

1.386

1.411

0.981

H

1.747

1.744

1.365

1.429

1.360

1.049

1.734

1.768

1.430

1.383

1.390

0.981

I

1.745

1.743

1.364

1.437

1.364

1.053

1.752

1.752

1.413

1.388

1.413

0.982