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	hartrees
Energy at 0K	-154.182724
Energy at 298.15K	-154.185640
HF Energy	-153.638673
Nuclear repulsion energy	98.516642

Mode Number	Symmetry	Frequency (cm^-1)	Scaled Frequency (cm^-1)	IR Intensities (km mol^-1)
1	A_g	3280	3124	0.00
2	A_g	1604	1528	0.00
3	A_g	1146	1092	0.00
4	A_g	976	930	0.00
5	A_u	731	696	0.00
6	A_u	499	475	0.00
7	B_1g	789	751	0.00
8	B_1u	3269	3113	24.02
9	B_1u	1632	1554	2.07
10	B_1u	1074	1023	0.37
11	B_2g	529	503	0.00
12	B_2u	3250	3095	13.04
13	B_2u	1296	1234	29.88
14	B_2u	756	720	7.67
15	B_3g	3235	3081	0.00
16	B_3g	1193	1136	0.00
17	B_3g	873	831	0.00
18	B_3u	576	549	123.53

Atom	y (Å)	z (Å)
C1	0.673	0.785
C2	0.673	-0.785
C3	-0.673	0.785
C4	-0.673	-0.785
H5	1.446	1.547
H6	1.446	-1.547
H7	-1.446	1.547
H8	-1.446	-1.547

	C1	C2	C3	C4	H5	H6	H7	H8
C1		1.5700	1.3454	2.0676	1.0854	2.4567	2.2512	3.1504
C2	1.5700		2.0676	1.3454	2.4567	1.0854	3.1504	2.2512
C3	1.3454	2.0676		1.5700	2.2512	3.1504	1.0854	2.4567
C4	2.0676	1.3454	1.5700		3.1504	2.2512	2.4567	1.0854
H5	1.0854	2.4567	2.2512	3.1504		3.0939	2.8913	4.2346
H6	2.4567	1.0854	3.1504	2.2512	3.0939		4.2346	2.8913
H7	2.2512	3.1504	1.0854	2.4567	2.8913	4.2346		3.0939
H8	3.1504	2.2512	2.4567	1.0854	4.2346	2.8913	3.0939

atom1	atom2	atom3	angle	atom1	atom2	atom3	angle
C1	C2	C4	90.000	C1	C2	H6	134.588
C1	C3	C4	90.000	C1	C3	H7	135.412
C2	C1	C3	90.000	C2	C1	H5	134.588
C2	C4	C3	90.000	C3	C1	H5	135.412
C4	C2	H6	135.412	C4	C3	H7	134.588

All results from a given calculation for C₄H₄ (cyclobutadiene)

using model chemistry: QCISD/6-31G*

States and conformations

	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 C4H4 (cyclobutadiene)

using model chemistry: QCISD/6-31G*

States and conformations

All results from a given calculation for C₄H₄ (cyclobutadiene)