Entry water_dimer_ccpvdz_PAR_HEA_v4_tapered__sha256_f4a38868cf406997 | QEncode

VQE Gap

1.5624e-4 Ha

CASCI ref

-152.062719 Ha

Qubits (tapered)

CCSD(T) corr.

-4.352e-1 Ha

Molecule / Problem

Namewater_dimer

Basis setcc-pvdz

GeometryO -1.551007 -0.114520 0.000000; H -1.934259 0.762503 0.000000; H -0.599677 0.040712 0.000000; O 1.350625 0.111469 0.000000; H 1.680398 -0.373741 -0.758561; H 1.680398 -0.373741 0.758561

Charge0

Spin0

Active electrons4

Active orbitals4

Orbital optimizationHF

Encoding / Circuit

Qubit mappingparity

Ansatz typehea

Ansatz reps (HEA)2

TaperingZ2 symmetry — 3 symmetries removed

Qubits (original)8

Qubits (tapered)5

Num parameters15

Circuit depth10

2Q gates8

Energy Results

HF energy-152.0625362496 Ha

MP2 energy-152.4734315200 Ha

CCSD energy-152.4912439611 Ha

CCSD(T) energy-152.4977225163 Ha

CASCI ground state-152.0627193590 Ha

VQE best energy-152.0625631236 Ha

|VQE − CASCI| gap1.562353e-4 Ha

CCSD(T) correlation-4.351863e-1 Ha

Optimizer / Run Config

AlgorithmCOBYLA

Multistart runs2

Max iterations500

Total func evals768

Num parameters15

Backenddefault.qubit

Provenance / Reproducibility

Entry IDwater_dimer_ccpvdz_PAR_HEA_v4_tapered__sha256_f4a38868cf406997

Schema version4.0.0

Created (UTC)2026-07-16T13:11:37.192642+00:00

SHA-256 hashf4a38868cf406997df6cc83d81f3062dfe11086390a3f036bc5bf5d9e4d50997

Python3.11.15

PySCF2.6.2

PennyLane0.45.0

OpenFermion1.6.1

NumPy2.2.6

SciPy1.13.1

Reproduce this result

# Clone repo and install pinned environment

git clone https://github.com/qencode-benchmark/qencode-benchmark

cd qencode-benchmark

pip install -r requirements-v4.txt

# Run this entry

python scripts/generate_entry_v4.py \

--molecule water_dimer \

--mapping parity \

--ansatz-type hea \

--reps 2 \

--multistart 2 \

--max-iter 500 \

--out-dir releases/v4/db

View raw JSON on GitHub