CCCBDB calculation results Page

using model chemistry: BLYP/3-21G*

States and conformations

State	Conformation	minimum conformation	conformer description	state description
1	2	yes	C2H	¹A_G

State

Conformation

minimum conformation

conformer description

state description

yes

C2H

¹A_G

Conformer 1 (D4H)

Jump to S1C2

Energy calculated at BLYP/3-21G*

	hartrees
Energy at 0K	-548.372183
Energy at 298.15K
HF Energy	-548.372183
Nuclear repulsion energy	347.080442

The energy at 298.15K was derived from the energy at 0K and an integrated heat capacity that used the calculated vibrational frequencies.

Vibrational Frequencies calculated at BLYP/3-21G*

Rotational Constants (cm^-1) from geometry optimized at BLYP/3-21G*
See section I.F.4 to change rotational constant units

Geometric Data calculated at BLYP/3-21G*

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability

Conformer 2 (C2H)

Jump to S1C1

Energy calculated at BLYP/3-21G*

	hartrees
Energy at 0K	-548.519555
Energy at 298.15K	-548.519335
HF Energy	-548.519555
Nuclear repulsion energy	343.234674

The energy at 298.15K was derived from the energy at 0K and an integrated heat capacity that used the calculated vibrational frequencies.

Vibrational Frequencies calculated at BLYP/3-21G*

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	1823	1811	0.00
2	A_g	1121	1114	0.00
3	A_g	578	574	0.00
4	A_g	226	224	0.00
5	A_g	210	209	0.00
6	A_u	1265	1256	289.61
7	A_u	825	820	6.40
8	A_u	616	612	0.00
9	A_u	181	180	0.17
10	A_u	160	159	0.00
11	B_g	1363	1355	0.00
12	B_g	730	726	0.00
13	B_g	486	483	0.00
14	B_g	472	469	0.00
15	B_u	1790	1778	63.21
16	B_u	936	930	106.81
17	B_u	285	283	4.76
18	B_u	223	222	0.18

Unscaled Zero Point Vibrational Energy (zpe) 6644.0 cm^-1
Scaled (by 0.9935) Zero Point Vibrational Energy (zpe) 6600.8 cm^-1
See section III.C.1 List or set vibrational scaling factors to change the scale factors used here.
See section III.C.2 Calculate a vibrational scaling factor for a given set of molecules to determine the least squares best scaling factor.

Rotational Constants (cm^-1) from geometry optimized at BLYP/3-21G*

A	B	C
0.07058	0.06682	0.03432

See section I.F.4 to change rotational constant units

Geometric Data calculated at BLYP/3-21G*

Point Group is C_2h

Cartesians (Å)

Atom	x (Å)	y (Å)	z (Å)
C1	0.000	0.818	0.669
C2	0.000	-0.818	0.669
C3	0.000	-0.818	-0.669
C4	0.000	0.818	-0.669
F5	0.000	1.702	1.691
F6	-0.000	-1.702	1.691
F7	-0.000	-1.702	-1.691
F8	0.000	1.702	-1.691

Atom - Atom Distances (Å)

	C1	C2	C3	C4	F5	F6	F7	F8
C1		1.6363	2.1143	1.3389	1.3510	2.7195	3.4532	2.5207
C2	1.6363		1.3389	2.1143	2.7195	1.3510	2.5207	3.4532
C3	2.1143	1.3389		1.6363	3.4532	2.5207	1.3510	2.7195
C4	1.3389	2.1143	1.6363		2.5207	3.4532	2.7195	1.3510
F5	1.3510	2.7195	3.4532	2.5207		3.4043	4.7988	3.3823
F6	2.7195	1.3510	2.5207	3.4532	3.4043		3.3823	4.7988
F7	3.4532	2.5207	1.3510	2.7195	4.7988	3.3823		3.4043
F8	2.5207	3.4532	2.7195	1.3510	3.3823	4.7988	3.4043

picture of tetrafluorcyclobutadiene state 1 conformation 2

More geometry information
Calculated Bond Angles

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C3	90.000	C1	C2	F6	130.867
C1	C4	C3	90.000	C1	C4	F8	139.133
C2	C1	C4	90.000	C2	C1	F5	130.867
C2	C3	C4	90.000	C2	C3	F7	139.133
C3	C2	F6	139.133	C3	C4	F8	130.867
C4	C1	F5	139.133	C4	C3	F7	130.867

Electronic energy levels

Charges, Dipole, Quadrupole and Polarizability
Charges from optimized geometry at BLYP/3-21G* Charges (e)

Number	Element	Mulliken
1	C	0.205
2	C	0.205
3	C	0.205
4	C	0.205
5	F	-0.205
6	F	-0.205
7	F	-0.205
8	F	-0.205

Electric dipole moments

Electric Quadrupole moment
Quadrupole components in D Å

Primitive
	x	y	z
x	-40.462	-0.000	0.000
y	-0.000	-42.015	0.000
z	0.000	0.000	-42.588

Traceless
	x	y	z
x	1.839	-0.000	0.000
y	-0.000	-0.489	0.000
z	0.000	0.000	-1.350

Polar
3z²-r²	-2.699
x²-y²	1.552
xy	-0.000
xz	0.000
yz	0.000

Polarizabilities
Components of the polarizability tensor.
Units are Å³ (Angstrom cubed)
Change units.

	x	y	z
x	2.068	0.000	0.000
y	0.000	5.540	0.000
z	0.000	0.000	7.431

<r²> (average value of r²) Å²

<r²>	260.119
(<r²>)^1/2	16.128

	Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
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All results from a given calculation for C4F4 (tetrafluorcyclobutadiene)

using model chemistry: BLYP/3-21G*

States and conformations

Conformer 1 (D4H)

Conformer 2 (C2H)

All results from a given calculation for C₄F₄ (tetrafluorcyclobutadiene)