Initialization

Needs["MaTeX`"]
SetOptions[MaTeX,"Preamble"->{"\\usepackage{amssymb,amsmath,latexsym,amsfonts,amsthm,xcolor,bm,mhchem}","\\definecolor{darkgreen}{RGB}{0, 180, 0}"}];

Cyclobutadiene

(Subscript[D, 2h])

Geometry

(Subscript[D, 2h]) geometry (in bohr) obtained at the CC3(full)/aug-cc-pVTZ

C         -1.47868321    -1.27004715     0.00000000
C          1.47868321    -1.27004715     0.00000000
C         -1.47868321     1.27004715     0.00000000
C          1.47868321     1.27004715     0.00000000
H         -2.91448237    -2.70994518    -0.00000000
H          2.91448237    -2.70994518     0.00000000
H         -2.91448237     2.70994518     0.00000000
H          2.91448237     2.70994518    -0.00000000

Data

(* %T1 (CC3/aug-cc-pVTZ)  98.7%, 95.0%, 0.84% *)

CBDD2h={
(* CC3 *)
{"CC3","6-31+G(d)",1.420,3.341,4.658},
{"","aug-cc-pVDZ",1.396,3.158,4.711},
{"","aug-cc-pVTZ",1.402,3.119,4.777},
{"","aug-cc-pVQZ",1.409,3.113,4.774},
(* CCSDT *)
{"CCSDT","6-31+G(d)",1.442,3.357,4.311},
{"","aug-cc-pVDZ",1.411,3.175,4.327},
{"","aug-cc-pVTZ",1.411,3.139,4.429},
(* CCSDT *)
 {"CCSDTQ","6-31+G(d)","",3.340,4.073},
(* CASSCF(4,4) *)
 {"SA2-CASSCF(4,4)","6-31+G(d)",1.662,4.657,4.439},
{"","aug-cc-pVDZ",1.672,4.563,4.448},
{"","aug-cc-pVTZ",1.670,4.546,4.441},
(* CASPT2(4,4) *)
 {"CASPT2(4,4)","6-31+G(d)",1.440,3.162,4.115},
{"","aug-cc-pVDZ",1.414,2.971,4.068},
{"","aug-cc-pVTZ",1.412,2.923,4.072},
(* SC-NEVPT2(4,4) *)
 {"SC-NEVPT2(4,4)","6-31+G(d)",1.407,2.707,4.145},
{"","aug-cc-pVDZ",1.381,2.479,4.109},
{"","aug-cc-pVTZ",1.379,2.422,4.108},
(* PC-NEVPT2(4,4) *)
 {"PC-NEVPT2(4,4)","6-31+G(d)",1.409,2.652,4.120},
{"","aug-cc-pVDZ",1.384,2.424,4.084},
{"","aug-cc-pVTZ",1.382,2.368,4.083},
(* MRCI(4,4) *)
 {"MRCI(4,4)","6-31+G(d)",1.564,3.802,4.265},
{"","aug-cc-pVDZ",1.558,3.670,4.254},
{"","aug-cc-pVTZ",1.568,3.678,4.270},
(* CASSCF(12,12) *)
 {"SA2-CASSCF(12,12)","6-31+G(d)","","",4.220},
{"","aug-cc-pVDZ",1.685,3.856,4.221},
{"","aug-cc-pVTZ",1.686,3.844,4.217},
(* CASPT2(12,12) *)
 {"CASPT2(12,12)","6-31+G(d)","","",""},
{"","aug-cc-pVDZ",1.489,3.256,4.044},
{"","aug-cc-pVTZ",1.480,3.183,4.043},
(* XMS-CASPT2(12,12) *)
 {"XMS-CASPT2(12,12)","6-31+G(d)","","",""},
{"","aug-cc-pVDZ","","",4.056},
{"","aug-cc-pVTZ","","",4.059},
(* SC-NEVPT2(12,12) *)
 {"SC-NEVPT2(12,12)","6-31+G(d)","","",4.130},
{"","aug-cc-pVDZ",1.511,3.266,4.093},
{"","aug-cc-pVTZ",1.501,3.188,4.086},
(* PC-NEVPT2(12,12) *)
 {"PC-NEVPT2(12,12)","6-31+G(d)","","",4.103},
{"","aug-cc-pVDZ",1.472,3.141,4.064},
{"","aug-cc-pVTZ",1.462,3.063,4.056},
(* CIPSI *)
 {"CIPSI","6-31+G(d)",Around[1.486 , 0.005],Around[3.388,0.053],Around[4.084,0.012]},
{"","aug-cc-pVDZ","",Around[3.187,0.027],Around[4.054,0.025]}
};

1.611717+2.63

Table of excitation energies

TableForm[CBDD2h,
TableHeadings->{None,{"Method","Basis","1 (^3)(Subscript[B, 1  g])","1 (^1)(Subscript[B, 1  g])","2 (^1)(Subscript[A, g])"}}, TableAlignments->Left]

Graph

ΔΕ=Table[CBDD2h[[;;,k]],{k,2,12}];
state=CBDD2h[[;;,1]];
method={"SF-TDB3LYP","SF-TDBH\\&HLYP","SF-CIS","SF-BSE@G$_0$W$_0$","SF-dBSE@G$_0$W$_0$","SF-ADC(2)-s","SF-ADC(2)-x","SF-ADC(3)","EOM-SF-CCSD","EOM-SF-CCSD(fT)","EOM-SF-CCSD(dT)"};
color={Red,Red,Red,Purple,Blue,Blue,Orange,Orange,Orange,Black,Black,Black};

Show[{
ListPlot[Table[Callout[Table[{2m-3/2,ΔΕ[[m,k]]},{m,Length[ΔΕ]}],state[[k]]],{k,3}],Joined->True,PlotStyle->{{LightGreen,Thickness[0.01]},{LightOrange,Thickness[0.01]},{LightRed,Thickness[0.01]},{LightPurple,Thickness[0.01]}}]
,
Show[
Table[Plot[If[2m-2≤x≤2m-1,ΔΕ[[m]]],{x,0,2Length[ΔΕ]-1},PlotStyle->Directive[Thick,color[[m]]]],{m,Length[ΔΕ]}]
]
},
PlotLabel->MaTeX["\\text{CBD (D$_{2h}$)}",FontSize->30],
Frame->True,Axes->False,PlotRange->{{-0.5,21.5},{1,5.6}},GridLines->{{5.5,7.5,11.5,17.5,23.5},Automatic},FrameTicks->{{Automatic,None},{Table[{2k-3/2,Rotate[MaTeX["\\text{"<>method[[k]]<>"}",FontSize->20],π/2]},{k,Length[method]}],None}},
BaseStyle->16,PlotRangePadding->0,FrameStyle->Directive[Thick,16,Black],AspectRatio->1,FrameLabel->{None,MaTeX["\\text{Excitation energy (eV)}",FontSize->24]},ImageSize->700]

`

(Subscript[D, 4h])

Data

CBDD4h={
(* CC3 *)
{"CC3","6-31+G(d)","","",""},
{"","aug-cc-pVDZ","","",""},
{"","aug-cc-pVTZ","","",""},
{"","aug-cc-pVQZ","","",""},
(* CIPSI *)
 {"CIPSI","6-31+G(d)",Around[,],Around[,],Around[,]},
{"","aug-cc-pVDZ",Around[,],Around[,],Around[,]}
};

Table of excitation energies

TableForm[CBDD4h,
TableHeadings->{None,{"Method","Basis","1 (^3)(Subscript[A, 2  g])","2 (^1)(Subscript[A, 1  g])","1 (^1)(Subscript[B, 2  g])"}}, TableAlignments->Left]